| 1. |
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| 2. |
- Haglund, Kaisa, et al.
(författare)
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Recruitment of Pyk2 and Cbl to lipid rafts mediates signals important for actin reorganization in growing neurites
- 2004
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Ingår i: Journal of Cell Science. ; 117:Pt12, s. 2557-2568
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Tidskriftsartikel (refereegranskat)abstract
- Protein tyrosine kinase Pyk2 and multifunctional adaptor protein Cbl are implicated in the regulation of the cytoskeleton in several cell types. We report that Pyk2 and Cbl form a signaling complex that is translocated to lipid rafts and is enriched in growth cones of differentiating PC12 cells following growth factor stimulation. We found that Pyk2 and Cbl interacted with the adaptor protein ArgBP2, which also bound to flotillin-1, a component of lipid raft microdomains. These interactions contributed to recruitment of the Pyk2/Cbl complex to lipid raft compartments. In addition, Pyk2, Cbl and ArgBP2 were found co-localized with actin in axons and growth cones of differentiated PC12 cells. Moreover, co-expression of Pyk2, ArgBP2 and Cbl facilitated growth factor-induced formation of lamellipodia at the tip of neurites. Formation of these growth cone lamellipodia was dependent on intact lipid rafts and the Cbl-associated effectors Crk and phosphatidylinositol 3 (PI 3)-kinase. Our results indicate that recruitment of Pyk2/Cbl complexes to lipid rafts participates in growth factor-induced regulation of the actin cytoskeleton in growing neurites.
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| 3. |
- Bandyopadhyay, Gautam, et al.
(författare)
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Glucose activates protein kinase C-zeta /lambda through proline-rich tyrosine kinase-2, extracellular signal-regulated kinase, and phospholipase D : A novel mechanism for activating glucose transporter translocation
- 2001
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Ingår i: J Biol Chem. - 0021-9258. ; 276:38, s. 35537-45
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Tidskriftsartikel (refereegranskat)abstract
- Insulin controls glucose uptake by translocating GLUT4 and other glucose transporters to the plasma membrane in muscle and adipose tissues by a mechanism that appears to require protein kinase C (PKC)-zeta/lambda operating downstream of phosphatidylinositol 3-kinase. In diabetes mellitus, insulin-stimulated glucose uptake is diminished, but with hyperglycemia, uptake is maintained but by uncertain mechanisms. Presently, we found that glucose acutely activated PKC-zeta/lambda in rat adipocytes and rat skeletal muscle preparations by a mechanism that was independent of phosphatidylinositol 3-kinase but, interestingly, dependent on the apparently sequential activation of the dantrolene-sensitive, nonreceptor proline-rich tyrosine kinase-2; components of the extracellular signal-regulated kinase (ERK) pathway, including, GRB2, SOS, RAS, RAF, MEK1 and ERK1/2; and, most interestingly, phospholipase D, thus yielding increases in phosphatidic acid, a known activator of PKC-zeta/lambda. This activation of PKC-zeta/lambda, moreover, appeared to be required for glucose-induced increases in GLUT4 translocation and glucose transport in adipocytes and muscle cells. Our findings suggest the operation of a novel pathway for activating PKC-zeta/lambda and glucose transport.
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| 4. |
- Blaukat, Andree, et al.
(författare)
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Activation of sphingosine kinase by the bradykinin B2 receptor and its implication in regulation of the ERK/MAP kinase pathway.
- 2001
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Ingår i: Biol Chem. - 1431-6730. ; 382:1, s. 135-9
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Tidskriftsartikel (refereegranskat)abstract
- Sphingosine kinase phosphorylates sphingosine to generate sphingosine 1-phosphate, a phospholipid that has been implicated in signaling by a number of transmembrane receptors and was recently shown to act as a ligand for a specific class of G protein-coupled receptors. Here we show that the G protein-coupled bradykinin B2 receptor activates sphingosine kinase leading to a time- and dose-dependent elevation of cellular sphingosine 1-phosphate levels that was blocked by the sphingosine kinase inhibitor dihydrosphingosine. Furthermore, increasing doses of this inhibitor partially affected the bradykinin-mediated ERK/MAP kinase activation and fully blocked the protein kinase C-independent component of the signaling pathway from the B2 receptor to the ERK/MAP kinase cascade. Overexpression of sphingosine kinase did not additionally increase the bradykinin-induced ERK/MAP kinase activity, indicating a permissive rather than activating role of sphingosine 1-phosphate in B2 receptor-mediated mitogenic signaling.
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| 5. |
- Blaukat, Andree, et al.
(författare)
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Determination of bradykinin B2 receptor in vivo phosphorylation sites and their role in receptor function
- 2001
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 276:44, s. 40431-40440
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Tidskriftsartikel (refereegranskat)abstract
- Reversible phosphorylation plays important roles in G protein-coupled receptor signaling, desensitization, and endocytosis, yet the precise location and role of in vivo phosphorylation sites is unknown for most receptors. Using metabolic 32P labeling and phosphopeptide sequencing we provide a complete phosphorylation map of the human bradykinin B2 receptor in its native cellular environment. We identified three serine residues, Ser(339), Ser(346), and Ser(348), at the C-terminal tail as principal phosphorylation sites. Constitutive phosphorylation occurs at Ser(348), while ligand-induced phosphorylation is found at Ser(339) and Ser(346)/Ser(348) that could be executed by several G protein-coupled receptor kinases. In addition, we found a protein kinase C-dependent phosphorylation of Ser(346) that was mutually exclusive with the basal phosphorylation at Ser(348) and therefore may be implicated in differential regulation of B2 receptor activation. Functional analysis of receptor mutants revealed that a low phosphorylation stoichiometry is sufficient to initiate receptor sequestration while a clustered phosphorylation around Ser(346) is necessary for desensitization of the B2 receptor-induced phospholipase C activation. This was further supported by the specifically reduced Ser(346)/Ser(348) phosphorylation observed upon stimulation with a nondesensitizing B2 receptor agonist. The differential usage of clustered phosphoacceptor sites points to distinct roles of multiple kinases in controlling G protein-coupled receptor function.
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| 6. |
- Dikic, Ivan, et al.
(författare)
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Cbl signaling networks in the regulation of cell function.
- 2003
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Ingår i: Cell Mol Life Sci. - 1420-682X. ; 60:9, s. 1805-27
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Forskningsöversikt (populärvet., debatt m.m.)abstract
- Cbl proteins control multiple cellular processes by acting as ubiquitin ligases and multifunctional adaptor molecules. They are involved in the control of cell proliferation, differentiation and cell morphology, as well as in pathologies such as autoimmune diseases, inflammation and cancer. Here we review recent advances in understanding the role of Cbl and the importance of a growing repertoire of Cbl-interacting proteins in the regulation of signaling pathways triggered by growth factors, antigens, cell adhesion, cytokines and hormones. We also address key issues of the nature of proteins that bind Cbl in particular cells, where they are located, and how they are altered or traffic within cells upon stimulation. It is becoming obvious that temporal and spatial changes in Cbl signaling networks are essential for the control of physiological processes in a variety of cells and organs and that their deregulation can result in the development of human diseases.
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| 7. |
- Dikic, Ivan
(författare)
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CIN85/CMS family of adaptor molecules.
- 2002
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Ingår i: FEBS Lett. - 0014-5793. ; 529:1, s. 110-5
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Forskningsöversikt (populärvet., debatt m.m.)abstract
- CIN85 and CMS belong to a family of ubiquitously expressed adaptor molecules containing three SH3 domains, a proline-rich region and a coiled-coil domain. By binding to numerous proteins they assemble multimeric complexes implicated in cell-specific signals controlling T-cell activation, kidney glomeruli function or apoptosis in neuronal cells. CIN85/CMS also associate with accessory endocytic proteins, components of the actin cytoskeleton as well as other adaptor proteins involved in receptor tyrosine kinase (RTK) signaling. These interactions enable CIN85/CMS to function within a network of signaling pathways that co-ordinate critical steps involved in downregulation and degradation of RTKs.
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| 8. |
- Freischmidt, Axel, et al.
(författare)
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Haploinsufficiency of TBK1 causes familial ALS and fronto-temporal dementia
- 2015
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Ingår i: Nature Neuroscience. - : Springer Science and Business Media LLC. - 1097-6256 .- 1546-1726. ; 18:5, s. 631-
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Tidskriftsartikel (refereegranskat)abstract
- Amyotrophic lateral sclerosis (ALS) is a genetically heterogeneous neurodegenerative syndrome hallmarked by adult-onset loss of motor neurons. We performed exome sequencing of 252 familial ALS (fALS) and 827 control individuals. Gene-based rare variant analysis identified an exome-wide significant enrichment of eight loss-of-function (LoF) mutations in TBK1 (encoding TANK-binding kinase 1) in 13 fALS pedigrees. No enrichment of LoF mutations was observed in a targeted mutation screen of 1,010 sporadic ALS and 650 additional control individuals. Linkage analysis in four families gave an aggregate LOD score of 4.6. In vitro experiments confirmed the loss of expression of TBK1 LoF mutant alleles, or loss of interaction of the C-terminal TBK1 coiled-coil domain (CCD2) mutants with the TBK1 adaptor protein optineurin, which has been shown to be involved in ALS pathogenesis. We conclude that haploinsufficiency of TBK1 causes ALS and fronto-temporal dementia.
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| 9. |
- Grabbe, Caroline, 1978-, et al.
(författare)
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Cell biology : going global on ubiquitin
- 2008
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 322:5903, s. 872-873
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Tidskriftsartikel (refereegranskat)
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| 10. |
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| 11. |
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| 12. |
- Grabbe, Caroline, et al.
(författare)
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The spatial and temporal organization of ubiquitin networks
- 2011
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Ingår i: Nature reviews. Molecular cell biology. - : Springer Science and Business Media LLC. - 1471-0072 .- 1471-0080. ; 12:5, s. 295-307
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Tidskriftsartikel (refereegranskat)abstract
- In the past decade, the diversity of signals generated by the ubiquitin system has emerged as a dominant regulator of biological processes and propagation of information in the eukaryotic cell. A wealth of information has been gained about the crucial role of spatial and temporal regulation of ubiquitin species of different lengths and linkages in the nuclear factor-κB (NF-κB) pathway, endocytic trafficking, protein degradation and DNA repair. This spatiotemporal regulation is achieved through sophisticated mechanisms of compartmentalization and sequential series of ubiquitylation events and signal decoding, which control diverse biological processes not only in the cell but also during the development of tissues and entire organisms.
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| 13. |
- Haglund, Kaisa, et al.
(författare)
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Cbl-directed monoubiquitination of CIN85 is involved in regulation of ligand-induced degradation of EGF receptors
- 2002
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 99:19, s. 12191-12196
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Tidskriftsartikel (refereegranskat)abstract
- Addition of ubiquitin or ubiquitin chains to target proteins leads to their mono- or polyubiquitination, respectively. Whereas polyubiquitination targets proteins for degradation, monoubiquitination is thought to regulate receptor internalization and endosomal sorting. Cbl proteins are major ubiquitin ligases that promote ligand-dependent polyubiquitination and degradation of receptor tyrosine kinases. They also recruit CIN85-endophilin in the complex with activated receptors, thus controlling receptor endocytosis. Here we show that the adaptor protein CIN85 and its homologue CMS are monoubiquitinated by Cbl/Cbl-b after epidermal growth factor (EGF) stimulation. Monoubiquitination of CIN85 required direct interactions between CIN85 and Cbl, the intact RING finger domain of Cbl and a ubiquitin acceptor site present in the carboxyl terminus of CIN85. Cbl-b and monoubiquitinated CIN85 are found in the complex with polyubiquitinated EGF receptors during prolonged EGF stimulation and are degraded together in the lysosome. Dominant interfering forms of CIN85, which have been shown previously to delay EGF receptor degradation, were also impaired in their monoubiquitination. Thus, our data demonstrate that Cbl/Cbl-b can mediate polyubiquitination of cargo as well as monoubiquitination of CIN85 to control endosomal sorting and degradation of receptor tyrosine kinases.
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| 14. |
- Haglund, Kaisa, et al.
(författare)
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Cindr interacts with anillin to control cytokinesis in Drosophila melanogaster
- 2010
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 20:10, s. 944-950
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Tidskriftsartikel (refereegranskat)abstract
- Cytokinesis, the final step of cell division, conventionally proceeds to cell separation by abscission, or complete cytokinesis [1, 2], but may in certain tissues be incomplete, yielding daughter cells that are interconnected in syncytia by stable intercellular bridges [3]. The mechanisms that determine complete versus incomplete cytokinesis are not known. Here we report a novel in vivo role of the Drosophila CD2AP/CIN85 ortholog Cindr in both complete and incomplete cytokinesis. We also show evidence for the presence of persistent intercellular bridges in the major larval imaginal disc epithelia. During conventional division of both cultured and embryonic cells, Cindr localizes to cleavage furrows, intercellular bridges, and midbodies. Moreover, in cells undergoing incomplete cytokinesis in the female germline and the somatic ovarian follicle cell and larval imaginal disc epithelia, Cindr localizes to arrested cleavage furrows and stable intercellular bridges, respectively. In these structures, Cindr colocalizes with the essential cytokinesis regulator Anillin. We show that Cindr interacts with Anillin and that depletion of either Cindr or Anillin gives rise to binucleate cells and fewer intercellular bridges in vivo. We propose that Cindr and Anillin cooperate to promote intercellular bridge stability during incomplete cytokinesis in Drosophila melanogaster.
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| 15. |
- Haglund, Kaisa, et al.
(författare)
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Multiple monoubiquitination of RTKs is sufficient for their endocytosis and degradation
- 2003
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Ingår i: Nature Cell Biology. - : Springer Science and Business Media LLC. - 1465-7392 .- 1476-4679. ; 5:5, s. 461-466
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Tidskriftsartikel (refereegranskat)abstract
- Many cellular proteins are post-translationally modified by the addition of a single ubiquitin or a polyubiquitin chain. Among these are receptor tyrosine kinases (RTKs), which undergo ligand-dependent ubiquitination. The ubiquitination of RTKs has become recognized as an important signal for their endocytosis and degradation in the lysosome; however, it is not clear whether ubiquitination itself is sufficient for this process or simply participates in its regulation. The issue is further complicated by the fact that RTKs are thought to be polyubiquitinated - a modification that is linked to protein degradation by the proteasome. By contrast, monoubiquitination has been associated with diverse proteasome-independent cellular functions including intracellular protein movement. Here we show that the epidermal growth factor and platelet-derived growth factor receptors are not polyubiquitinated but rather are monoubiquitinated at multiple sites after their ligand-induced activation. By using different biochemical and molecular genetics approaches, we show that a single ubiquitin is sufficient for both receptor internalization and degradation. Thus, monoubiquitination is the principal signal responsible for the movement of RTKs from the plasma membrane to the lysosome.
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| 16. |
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| 17. |
- Haglund, Kaisa, 1978-
(författare)
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Ubiquitination and Receptor Endocytosis
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Protein ubiquitination is an evolutionary conserved mechanism that controls a wide variety of cellular functions. Polyubiquitinated proteins are generally degraded in the proteasome, whereas monoubiquitination controls various other cellular processes, including endocytosis and endosomal sorting.Termination of signaling by activated receptor tyrosine kinases (RTKs) largely occurs via their endocytosis and subsequent lysosomal degradation, processes accompanied by receptor ubiquitination. Cbl family proteins are major ubiquitin ligases that promote RTK ubiquitination and downregulation. We showed that epidermal growth factor (EGF) and platelet derived growth factor (PDGF) receptors are monoubiquitinated at multiple sites following their ligand-induced activation and that a single ubiquitin is sufficient for both receptor internalization and degradation. Cbl also controls EGF receptor (EGFR) downregulation by binding to CIN85, which recruits endophilins to EGFR/Cbl complexes. In the complex with activated EGFRs, Cbl directs monoubiquitination of CIN85, and the entire complex is targeted for degradation in the lysosome. We propose that multiple monoubiquitination of activated receptors and associated protein complexes ensures proper receptor sorting towards the lysosome. Importantly, the functions of Cbl are also negatively controlled in order to maintain cellular homestasis. Sprouty2 blocks EGFR downregulation by sequestering Cbl from activated EGFRs. We showed that Sprouty2 also associates with CIN85 and that this binding is required for efficient inhibition of EGFR ubiquitination and endocytosis. Cbl is also implicated in other aspects of RTK signaling, including organization of the actin cytoskeleton. We found that growth factor receptor signals promote lamellipodia formation in neuronal cells via a complex containing Cbl, the adaptor protein ArgBP2 and Pyk2. The lamellipodia formation required intact lipid rafts and the recruitment of Crk and PI(3)K to tyrosine phosphorylated Cbl.In conclusion, our findings contribute to a better understanding of monoubiquitin signals in downregulation of RTKs and point at a role of Cbl in the regulation of cytoskeleton dynamics.
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| 18. |
- Ikeda, Fumiyo, et al.
(författare)
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SHARPIN forms a linear ubiquitin ligase complex regulating NF-κB activity and apoptosis.
- 2011
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 471:7340, s. 637-641
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Tidskriftsartikel (refereegranskat)abstract
- SHARPIN is a ubiquitin-binding and ubiquitin-like-domain-containing protein which, when mutated in mice, results in immune system disorders and multi-organ inflammation. Here we report that SHARPIN functions as a novel component of the linear ubiquitin chain assembly complex (LUBAC) and that the absence of SHARPIN causes dysregulation of NF-κB and apoptotic signalling pathways, explaining the severe phenotypes displayed by chronic proliferative dermatitis (cpdm) in SHARPIN-deficient mice. Upon binding to the LUBAC subunit HOIP (also known as RNF31), SHARPIN stimulates the formation of linear ubiquitin chains in vitro and in vivo. Coexpression of SHARPIN and HOIP promotes linear ubiquitination of NEMO (also known as IKBKG), an adaptor of the IκB kinases (IKKs) and subsequent activation of NF-κB signalling, whereas SHARPIN deficiency in mice causes an impaired activation of the IKK complex and NF-κB in B cells, macrophages and mouse embryonic fibroblasts (MEFs). This effect is further enhanced upon concurrent downregulation of HOIL-1L (also known as RBCK1), another HOIP-binding component of LUBAC. In addition, SHARPIN deficiency leads to rapid cell death upon tumour-necrosis factor α (TNF-α) stimulation via FADD- and caspase-8-dependent pathways. SHARPIN thus activates NF-κB and inhibits apoptosis via distinct pathways in vivo.
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| 19. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 20. |
- Kowanetz, Katarzyna, 1977-
(författare)
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Adaptor Proteins in Regulation of Receptor Endocytosis
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ligand-induced endocytosis of receptor tyrosine kinases (RTKs) is a dynamic process governed by numerous protein-protein and protein-lipid interactions. This is a major mechanism of signal termination and is also frequently impaired in cancer. The Cbl family of ubiquitin ligases has been shown to play a key role in downregulation of RTKs, by directing their ligand-induced ubiquitination and subsequent lysosomal degradation. My thesis work has led to the identification of novel, ubiquitin-ligase independent, functions of Cbl in receptor endocytosis. We demonstrated that the adaptor protein CIN85 links Cbl with epidermal growth factor receptor (EGFR) internalization. The three SH3 domains of CIN85 interact with Cbl/Cbl-b in a phosphotyrosine dependent manner, whereas its proline-rich region constitutively binds endophilins, known regulators of plasma membrane invagination. The SH3 domains of CIN85 recognize an atypical proline-arginine (PxxxPR) motif present in Cbl and Cbl-b. Moreover, we showed that numerous endocytic regulatory proteins, among them ASAP1 and Dab2, interact with CIN85 via their PxxxPR motifs. The SH3 domains of CIN85 are able to cluster and exchange its effectors at subsequent stages of EGFR endocytosis, thus participating in the control of receptor internalization, recycling and degradation in the lysosome. We proposed that CIN85 functions as a scaffold molecule implicated in control of multiple steps in downregulation of RTKs.Furthermore, we identified two novel Cbl- and ubiquitin-interacting adaptor proteins named Sts-1 and Sts-2 (Suppressors of T-cell receptor signaling). Ligand-induced and Cbl-mediated recruitment of Sts-1/Sts-2 into activated EGFR complexes led to inhibition of receptor internalization and subsequent block of receptor degradation followed by prolonged mitogenic signaling pathways. Our results indicate that Sts-1 and Sts-2 represent a new class of negative regulators of Cbl functions in receptor endocytosis.In conclusion, this thesis describes novel mechanisms by which Cbl, coupled to its effectors, orchestrates trafficking of RTKs. Detailed understanding of how these processes are controlled under physiological as well as under pathological conditions may be important for future therapeutic approaches.
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| 21. |
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| 22. |
- Kowanetz, Katarzyna, et al.
(författare)
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CIN85 associates with multiple effectors controlling intracellular trafficking of epidermal growth factor receptors.
- 2004
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Ingår i: Mol Biol Cell. - 1059-1524. ; 15:7, s. 3155-66
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Tidskriftsartikel (refereegranskat)abstract
- CIN85 is a multidomain adaptor protein involved in Cbl-mediated down-regulation of epidermal growth factor (EGF) receptors. CIN85 src homology 3 domains specifically bind to a proline-arginine (PxxxPR) motif in Cbl, and this association seems to be important for EGF receptor endocytosis. Here, we report identification of novel CIN85 effectors, all containing one or more PxxxPR motifs, that are indispensable for their mutual interactions. These effectors include phosphatidyl-inositol phosphatases SHIP-1 and synaptojanin 2B1, Arf GTPase-activating proteins ASAP1 and ARAP3, adaptor proteins Hip1R and STAP1, and a Rho exchange factor, p115Rho GEF. Acting as a molecular scaffold, CIN85 clusters its effectors and recruits them to high-molecular-weight complexes in cytosolic extracts of cells. Further characterization of CIN85 binding to ASAP1 revealed that formation of the complex is independent on cell stimulation. Overexpression of ASAP1 increased EGF receptor recycling, whereas ASAP1 containing mutated PxxxPR motif failed to promote this event. We propose that CIN85 functions as a scaffold molecule that binds to numerous endocytic accessory proteins, thus controlling distinct steps in trafficking of EGF receptors along the endocytic and recycling pathways.
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| 23. |
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| 24. |
- Kowanetz, Katarzyna, et al.
(författare)
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Dab2 links CIN85 with clathrin-mediated receptor internalization.
- 2003
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Ingår i: FEBS Lett. - 0014-5793. ; 554:1-2, s. 81-7
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Tidskriftsartikel (refereegranskat)abstract
- CIN85 is a multidomain scaffold protein involved in downregulation of receptor tyrosine kinases. Here we show that disabled-2 (Dab2), an endocytic adaptor molecule implicated in clathrin-coat assembly, associates with CIN85 in mammalian cells. All three SH3 domains of CIN85 were able to bind to the PKPAPR peptide in the carboxyl-terminal part of Dab2, possibly enabling CIN85 to simultaneously interact with multiple Dab2 molecules. CIN85 association with Dab2 is essential for its recruitment to clathrin coat and appears to be modulated by growth factor stimulation. Dab2 and clathrin dissociated from CIN85 following growth factor treatment, enabling other molecules, such as Cbl, to bind to CIN85. Taken together, our data indicate a dynamic interplay between CIN85 and its effectors during endocytosis of receptor tyrosine kinases.
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| 25. |
- Kowanetz, Katarzyna, et al.
(författare)
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Identification of a novel proline-arginine motif involved in CIN85-dependent clustering of Cbl and down-regulation of epidermal growth factor receptors
- 2003
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 278:41, s. 39735-39746
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Tidskriftsartikel (refereegranskat)abstract
- CIN85 is a multidomain adaptor protein implicated in Cbl-mediated down-regulation of receptor tyrosine kinases. CIN85 binding to Cbl is increased after growth factor stimulation and is critical for targeting receptor tyrosine kinases to clathrin-mediated endocytosis. Here we report the identification of a novel polyproline-arginine motif (PXXXPR), specifically recognized by the SH3 domains of CIN85 and its homologue CMS/CD2AP. This motif was indispensable for CIN85 binding to Cbl/Cbl-b, to other CIN85 SH3 domains' effectors, and for mediating an intramolecular interaction between the SH3-A domain and the proline-rich region of CIN85. Individual SH3 domains of CIN85 bound to PXXXPR peptides of Cbl/Cbl-b with micromolar affinities, whereas an extended structure of two or three SH3 domains bound with higher stoichiometry and increased affinity to the same peptides. This enabled full size CIN85 to simultaneously interact with multiple Cbl molecules, promoting their clustering in mammalian cells. The ability of CIN85 to cluster Cbl was important for ligand-induced stabilization of CIN85.Cbl.epidermal growth factor receptor complexes, as well as for epidermal growth factor receptor degradation in the lysosome. Thus, specific interactions of CIN85 SH3 domains with the PXXXPR motif in Cbl play multiple roles in down-regulation of receptor tyrosine kinases.
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