Figure 6

Physical interaction between CalpB and talin in Drosophila . ( A) Talin is an in vitro substrate of CalpB. Crude protein extracts of stage 2 embryos were analyzed directly (0’) or were treated with recombinant CalpB for 5 minutes (5’) in the absence and presence of 20 mM Ca²⁺ or 10 mM EDTA. An untreated extract from CalpB⁵⁰⁵ embryos was also tested for comparison. The proteolytic fragmentation of talin was investigated by Western blotting using a talin-specific antibody (upper section). The loading of the lanes was tested by a tubulin-specific antibody (lower section). St denotes molecular mass standards; the positions of two pre-stained bands are labeled at the left side, and arrows indicate the main immunoreactive talin bands at the right side. (B) Coimmunoprecipitation of talin with CalpB. Immunoprecipitations were performed in embryonic extracts with anti-Talin antibody, and the immunoblots were stained with anti-CalpB antibody. The positions of the full-length CalpB bands are marked by the arrow.