| 1. |
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| 2. |
- Gramolelli, Silvia, et al.
(författare)
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PROX1 is a transcriptional regulator of MMP14
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The transcription factor PROX1 is essential for development and cell fate specification. Its function in cancer is context-dependent since PROX1 has been shown to play both oncogenic and tumour suppressive roles. Here, we show that PROX1 suppresses the transcription of MMP14, a metalloprotease involved in angiogenesis and cancer invasion, by binding and suppressing the activity of MMP14 promoter. Prox1 deletion in murine dermal lymphatic vessels in vivo and in human LECs increased MMP14 expression. In a hepatocellular carcinoma cell line expressing high endogenous levels of PROX1, its silencing increased both MMP14 expression and MMP14-dependent invasion in 3D. Moreover, PROX1 ectopic expression reduced the MMP14-dependent 3D invasiveness of breast cancer cells and angiogenic sprouting of blood endothelial cells in conjunction with MMP14 suppression. Our study uncovers a new transcriptional regulatory mechanism of cancer cell invasion and endothelial cell specification.
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| 3. |
- Gupta, Deepesh Kumar
(författare)
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Adhesion-dependent mechanisms regulating mitosis
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Integrin-mediated cell adhesion is required for normal cell cycle progression during G1-S transition and for the completion of cytokinesis. Cancer cells have ability to grow anchorage-independently, but the underlying mechanisms and the functional significance for cancer development are unclear. The current thesis describes new data on the adhesion-linked molecular mechanisms regulating cytokinesis and centrosomes. Non-adherent fibroblast failed in the last step of the cytokinesis process, the abscission. This was due to lack of CEP55-binding of ESCRT-III and its associated proteins to the midbody (MB) in the intercellular bridge (ICB), which in turn correlated with too early disappearance of PLK1 and the consequent premature CEP55 accumulation. Integrin-induced FAK activity was found to be an important upstream step in the regulation of PLK1 and cytokinetic abscission. Under prolonged suspension culture, the MB disappeared but septin filaments kept the ICB in the ingressed state. Upon re-plating on fibronectin, such cells were found to divide through traction-based abscission. Non-adherent cytokinetic cells maintained septin filaments around the ICB for >24 hours, but septin was gradually depolymerized later on and furrow-regressed binucleated cells were generated (<15%). Binucleated non-transformed cells were halted in G1 and became senescent, possibly via PIDDosome formation by two centrosomes merging. In contrast to normal fibroblasts, ras-transformed fibroblasts were able to recruit the ESCRT-III-associated protein ALIX to MB under non-adherent condition. Live-cell imaging and septin-7 immuno-staining showed that cytokinetic abscission occurred in non-adherent ras-transformed fibroblast. Non-adherent fibroblasts, as well as adherent cells lacking FAK expression, were also delayed in early stages of mitosis progression and exhibited defect centrosome separation and abnormal spindle formation. Our data show that integrin-dependent FAK activity promotes centrosome separation via a FAK-PLK1-Eg5 route during early mitosis.
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| 4. |
- 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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| 5. |
- 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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| 6. |
- 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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| 7. |
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| 8. |
- 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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| 9. |
- 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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| 10. |
- 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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