Mechanosensing is an integral part of cell migration and involves the transduction of mechanical cues from the extracellular environment into the cell through focal adhesions. Focal adhesions are comprised of a large group of cytoplasmic proteins that link the actin cytoskeleton of the cell to the extracellular matrix (ECM) and provide the nexus for mechanical communication. Focal adhesions are dynamic structures whose formation and disassembly rely on tyrosine phosphorylation and proteolysis of adhesion component proteins. Calpains are a group of calcium-dependent proteases known to be involved in focal adhesion turnover by cleaving proteins within the adhesion. We have previously shown that when the proteolytic subunits, Capn1, Capn2, or their regulatory subunit, Capn4 is knocked down, mechanosensing abilities of the cell are also decreased. We screened for proteins expressing differential tyrosine phosphorylation in each of these calpain deficient cells and compared the values to wild type MEFs. One protein discovered through this screening was NM23-M2, a nucleoside diphosphate kinase. We have examined the mechanosensing ability of NM23-M2 knockdown cells and have found they are defective in sensing an applied mechanical stimulus, however they have no defect in the production of traction stress. Additionally, we have shown NM23-M2 is secreted, and speculate that secretion is linked to its tyrosine phosphorylation.
|Advisor:||Beningo, Karen A.|
|Commitee:||Ansari, Athar, Tucker, James|
|School:||Wayne State University|
|School Location:||United States -- Michigan|
|Source:||MAI 50/04M, Masters Abstracts International|
|Subjects:||Cellular biology, Biophysics|
|Keywords:||Mechanosensing, Metastatic cells, Traction stress|
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