The name nexilin
came from the Latin word nexilis, meaning 'bound together.' Full-length b-nexilin contains an N-terminal F-actin-binding domain (ABD), followed by a spacer, a coiled-coil region, a second ABD, and a long C-terminal tail. In comparison, s-nexilin lacks the N-terminal ABD and has an insertion in the C-terminal tail. Immunofluorescence microscopy revealed that both b-nexilin and s-nexilin colocalized with F-actin at focal contacts at the ends of stress fibers.
The nexilins did not localize to cell-cell junctions. Western blot analysis detected nexilin proteins with apparent molecular masses above 90 kD in rat brain, testis, and spleen and in cultured rodent fibroblasts. Neither protein was detected in liver, kidney, or epithelial cell lines.