| 1. |
- Holmgren, Christian, et al.
(författare)
-
Molecular characterization of protein kinase C delta (PKCδ)-Smac interactions
- 2016
-
Ingår i: BMC Biochemistry. - : Springer Science and Business Media LLC. - 1471-2091. ; 17:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Protein kinase C o (PKCo) is known to be an important regulator of apoptosis, having mainly pro-but also anti-Apoptotic effects depending on context. In a previous study, we found that PKCo interacts with the pro-Apoptotic protein Smac. Smac facilitates apoptosis by suppressing inhibitor of apoptosis proteins (IAPs). We previously established that the PKCo-Smac complex dissociates during induction of apoptosis indicating a functional importance. Because the knowledge on the molecular determinants of the interaction is limited, we aimed at characterizing the interactions between PKCo and Smac. Results: We found that PKCo binds directly to Smac through its regulatory domain. The interaction is enhanced by the PKC activator TPA and seems to be independent of PKCo catalytic activity since the PKC kinase inhibitor GF109203X did not inhibit the interaction. In addition, we found that C1 and C2 domains from several PKC isoforms have Smac-binding capacity. Conclusions: Our data demonstrate that the Smac-PKCo interaction is direct and that it is facilitated by an open conformation of PKCo. The binding is mediated via the PKCo regulatory domain and both the C1 and C2 domains have Smac-binding capacity. With this study we thereby provide molecular information on an interaction between two apoptosis-regulating proteins.
|
|
| 2. |
- Ke, Hengning, et al.
(författare)
-
Nemo-like kinase regulates the expression of vascular endothelial growth factor (VEGF) in alveolar epithelial cells
- 2016
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- The canonical Wnt signaling can be silenced either through β-catenin-mediated ubiquitination and degradation or through phosphorylation of Tcf and Lef by nemo-like kinase (NLK). In the present study, we generated NLK deficient animals and found that these mice become cyanotic shortly before death because of lung maturation defects. NLK-/- lungs exhibited smaller and compressed alveoli and the mesenchyme remained thick and hyperplastic. This phenotype was caused by epithelial activation of vascular endothelial growth factor (VEGF) via recruitment of Lef1 to the promoter of VEGF. Elevated expression of VEGF and activation of the VEGF receptor through phosphorylation promoted an increase in the proliferation rate of epithelial and endothelial cells. In summary, our study identifies NLK as a novel signaling molecule for proper lung development through the interconnection between epithelial and endothelial cells during lung morphogenesis.
|
|
| 3. |
|
|
| 4. |
- Masoumi, Katarzyna Chmielarska, et al.
(författare)
-
NLK-mediated phosphorylation of HDAC1 negatively regulates Wnt signaling
- 2017
-
Ingår i: Molecular Biology of the Cell. - 1059-1524. ; 28:2, s. 346-355
-
Tidskriftsartikel (refereegranskat)abstract
- The Wnt signaling pathway is essential in regulating various cellular processes. Different mechanisms of inhibition for Wnt signaling have been proposed. Besides β-catenin degradation through the proteasome, nemo-like kinase (NLK) is another molecule that is known to negatively regulate Wnt signaling. However, the mechanism by which NLK mediates the inhibition of Wnt signaling was not known. In the present study, we used primary embryonic fibroblast cells isolated from NLK-deficient mice and showed that these cells proliferate faster and have a shorter cell cycle than wild-type cells. In NLK-knockout cells, we observed sustained interaction between Lef1 and β-catenin, leading to elevated luciferase reporter of β-catenin/Lef1-mediated transcriptional activation. The mechanism for the reduced β-catenin/Lef1 promoter activation was explained by phosphorylation of HDAC1 at serine 421 via NLK. The phosphorylation of HDAC1 was achieved only in the presence of wild-type NLK because a catalytically inactive mutant of NLK was unable to phosphorylate HDAC1 and reduced the luciferase reporter of β-catenin/Lef1-mediated transcriptional activation. This result suggests that NLK and HDAC1 together negatively regulate Wnt signaling, which is vital in preventing aberrant proliferation of nontransformed primary fibroblast cells.
|
|
| 5. |
- Sime, Wondossen, et al.
(författare)
-
BAP1 induces cell death via interaction with 14-3-3 in neuroblastoma article
- 2018
-
Ingår i: Cell Death and Disease. - : Springer Science and Business Media LLC. - 2041-4889. ; 9:5
-
Tidskriftsartikel (refereegranskat)abstract
- BRCA1-associated protein 1 (BAP1) is a nuclear deubiquitinating enzyme that is associated with multiprotein complexes that regulate key cellular pathways, including cell cycle, cellular differentiation, cell death, and the DNA damage response. In this study, we found that the reduced expression of BAP1 pro6motes the survival of neuroblastoma cells, and restoring the levels of BAP1 in these cells facilitated a delay in S and G2/M phase of the cell cycle, as well as cell apoptosis. The mechanism that BAP1 induces cell death is mediated via an interaction with 14-3-3 protein. The association between BAP1 and 14-3-3 protein releases the apoptotic inducer protein Bax from 14-3-3 and promotes cell death through the intrinsic apoptosis pathway. Xenograft studies confirmed that the expression of BAP1 reduces tumor growth and progression in vivo by lowering the levels of pro-survival factors such as Bcl-2, which in turn diminish the survival potential of the tumor cells. Patient data analyses confirmed the finding that the high-BAP1 mRNA expression correlates with a better clinical outcome. In summary, our study uncovers a new mechanism for BAP1 in the regulation of cell apoptosis in neuroblastoma cells.
|
|
| 6. |
- Thorén, Matilda Munksgaard, et al.
(författare)
-
Integrin α10, a novel therapeutic target in glioblastoma, regulates cell migration, proliferation, and survival
- 2019
-
Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 11:4
-
Tidskriftsartikel (refereegranskat)abstract
- New, effective treatment strategies for glioblastomas (GBMs), the most malignant and invasive brain tumors in adults, are highly needed. In this study, we investigated the potential of integrin α10Β1 as a therapeutic target in GBMs. Expression levels and the role of integrin α10Β1 were studied in patient-derived GBM tissues and cell lines. The effect of an antibody-drug conjugate (ADC), an integrin a10 antibody conjugated to saporin, on GBM cells and in a xenograft mouse model was studied. We found that integrin α10Β1 was strongly expressed in both GBM tissues and cells, whereas morphologically unaffected brain tissues showed only minor expression. Partial or no overlap was seen with integrins α3, α6, and α7, known to be expressed in GBM. Further analysis of a subpopulation of GBM cells selected for high integrin α10 expression demonstrated increased proliferation and sphere formation. Additionally, siRNA-mediated knockdown of integrin α10 in GBM cells led to decreased migration and increased cell death. Furthermore, the ADC reduced viability and sphere formation of GBM cells and induced cell death both in vitro and in vivo. Our results demonstrate that integrin α10Β1 has a functional role in GBM cells and is a novel, potential therapeutic target for the treatment of GBM.
|
|
