Phospho-Talin (Ser425) Recombinant Rabbit mAb (S-4905)

Phospho-Talin (Ser425) refers to the phosphorylation of the focal adhesion protein talin at serine residue 425, a modification catalyzed by cyclin-dependent kinase 5 (Cdk5) that regulates talin head domain turnover and cell migration. Talin is a large multidomain protein (225–270 kDa) that links integrins to the actin cytoskeleton at focal adhesions, and is essential for integrin activation and focal adhesion formation. Following calpain-mediated cleavage, the talin head domain is generated and acts as a substrate for Cdk5, which phosphorylates Ser425 both in vitro and in vivo. This phosphorylation inhibits the binding of the talin head domain to the E3 ubiquitin ligase Smurf1, thereby preventing Smurf1-mediated ubiquitination and proteasomal degradation of the talin head. Expression of the non-phosphorylatable mutant talin(S425A), which increases its susceptibility to Smurf1-mediated ubiquitination, results in extensive focal adhesion turnover and inhibits cell migration, whereas the phosphomimetic mutant talin(S425D) leads to more persistent protrusions and impaired migration. This Cdk5-dependent phosphorylation of talin Ser425 has been shown to be important for neuronal cell migration and is implicated in colorectal cancer progression and metastasis, making it a potential tumor marker and therapeutic target.