14 research outputs found
MELK Promotes Melanoma Growth by Stimulating the NF-kappaB Pathway
Melanoma accounts for more than 80% of skin cancer-related deaths, and current therapies provide only short-term benefit to patients. Here, we show in melanoma cells that maternal embryonic leucine zipper kinase (MELK) is transcriptionally upregulated by the MAPK pathway via transcription factor E2F1. MELK knockdown or pharmacological inhibition blocked melanoma growth and enhanced the effectiveness of BRAFV600E inhibitor against melanoma cells. To identify mediators of MELK function, we performed stable isotope labeling with amino acids in cell culture (SILAC) and identified 469 proteins that had downregulated phosphorylation after MELK inhibition. Of these proteins, 139 were previously reported as substrates of BRAF or MEK, demonstrating that MELK is an important downstream mediator of the MAPK pathway. Furthermore, we show that MELK promotes melanoma growth by activating NF-kappaB pathway activity via Sequestosome 1 (SQSTM1/p62). Altogether, these results underpin an important role for MELK in melanoma growth downstream of the MAPK pathway
MELK Promotes Melanoma Growth by Stimulating the NF-ÎşB Pathway
Summary: Melanoma accounts for more than 80% of skin cancer-related deaths, and current therapies provide only short-term benefit to patients. Here, we show in melanoma cells that maternal embryonic leucine zipper kinase (MELK) is transcriptionally upregulated by the MAPK pathway via transcription factor E2F1. MELK knockdown or pharmacological inhibition blocked melanoma growth and enhanced the effectiveness of BRAFV600E inhibitor against melanoma cells. To identify mediators of MELK function, we performed stable isotope labeling with amino acids in cell culture (SILAC) and identified 469 proteins that had downregulated phosphorylation after MELK inhibition. Of these proteins, 139 were previously reported as substrates of BRAF or MEK, demonstrating that MELK is an important downstream mediator of the MAPK pathway. Furthermore, we show that MELK promotes melanoma growth by activating NF-κB pathway activity via Sequestosome 1 (SQSTM1/p62). Altogether, these results underpin an important role for MELK in melanoma growth downstream of the MAPK pathway. : Janostiak et al. find that MELK is overexpressed in melanoma and is necessary for melanoma growth. MELK regulates the NF-κB pathway via SQSTM1, which is necessary partly for its ability to promote melanoma growth. Keywords: MELK, melanoma, BRAF, SILAC, NF-κB, SQSTM
Phosphorylation at Y1065 in Vinculin Mediates Actin Bundling, Cell Spreading, and Mechanical Responses to Force
Vinculin
is an essential structural adaptor protein that localizes
to sites of adhesion and is involved in a number of cell processes
including adhesion, spreading, motility, force transduction, and cell
survival. The C-terminal vinculin tail domain (Vt) contains the necessary
structural components to bind and cross-link actin filaments. Actin
binding to Vt induces a conformational change that promotes dimerization
through the C-terminal hairpin of Vt and enables actin filament cross-linking.
Here we show that Src phosphorylation of Y1065 within the C-terminal
hairpin regulates Vt-mediated actin bundling and provide a detailed
characterization of Y1065 mutations. Furthermore, we show that phosphorylation
at Y1065 plays a role in cell spreading and the response to the application
of mechanical force