Src Kinase Signaling Inhibitor 1 (SRCIN1)

Indirect immunofluorescence and confocal microscopy of rat PC12 pheochromocytoma cells revealed colocalization of Snip with Snap25 in the actin cytoskeleton, particularly in filopodia, lamellipodia, and neuritic extensions, including the tips. The deduced Snip-A and Snip-B proteins contain 1,173 and 1,197 amino acids, respectively, and differ only at their C termini. Both proteins have a proline-rich domain, followed by 2 coiled-coil domains, a charged region, a second proline-rich domain, and a second charged region. The proline-rich domains contain multiple PPxY and PxxP motifs involved in protein-protein interactions. Western blot analysis of various rat tissues detected a 145-kD protein in brain and a 95-kD protein in testis, and Snip showed moderate to high expression in most specific brain regions examined.