Figure 1.

Identification of fimbrin-binding proteins present in the Triton X-100 extracts from adherent P388D1 cells. (A) Proteins immunoprecipitated with fimbrin antibodies were separated on two-dimensional gels and detected by silver stain. Four polypeptides of molecular mass 45,000, 55,000, 68,000, and 75,000 Da were precipitated with fimbrin antisera and were not present in control antisera. The four proteins were identified from their tryptic mass fingerprints as actin (45,000), vimentin (55,000), fimbrin (68,000), and HSP-70 (75,000). Other polypeptides on the gel were also present in the control antisera and were not characterized further. (B) In a fimbrin overlay assay of proteins electroblotted onto PVDF membranes, only the 45-, 55-, and 75-kD proteins bind the biotinylated fimbrin probe.