<p><i>A</i>) Nexilin selectively binds to IRS1 in L6 skeletal muscle cells. Serum starved L6 myotubes were left untreated or stimulated with 100 nM insulin for the indicated times. Cell lysates were immunoprecipitated (IP) with either IRS1 or IRS2 antibodies (abs) and subjected to western blot analysis with the indicated abs. WCL, whole cell lysates; <i>B</i>) Schematic representation of nexilin constructs. The isolated open reading frame of s-nexilin predicts a protein of 611 amino acids (aa) and consists of a central coiled-coil (CC) domain flanked by two F-actin binding domains (ABD). Nexilin-#2 is a truncated version containing the CC and second ABD domain (aa. 155–419) Nexilin-#3 consists of the second ABD domain (aa 240–410). Nexilin-#4 contains the N-terminal ABD and CC domains (aa 1–237). <i>C</i>) HEK293 cells were transfected with either pCMV5b vector (C), full length (FL) pCMV5b/Flag-nexilin construct or Flag-tagged nexilin-#2, #3 or #4 constructs. Cells were co-transfected with HA-IRS1. Left Panel, Lysates were immunoprecipitated with HA abs and blotted with either Flag or HA abs. Right Panel, Whole cell lysates (WCL) from transfected cells were immunoblotted with Flag abs showing expression of recombinant nexilin proteins.</p
