Fig. 6. Binding of filamin isoforms and variants to GST-myotilin and GST-FATZ-1 fusion proteins. (A) HA-tagged recombinant form of filamin-A (FLN-A), filamin-B (FLN-B), filamin-ß_Var-1 (FLN-B_var-1) and filamin-C (FLN-C), containing repeats 19-24 were generated by coupled in vitro transcription/translation and analyzed by SDS-PAGE and autoradiography. The positions of FLN-A, FLN-B and FLN-B_var-1 (arrowhead), and FLN-C (arrow) are indicated. (B,C) GST-fusion proteins immobilized on glutathione-agarose beads were incubated with the various radiolabeled filamin recombinants. After washing, bound proteins were analyzed by SDS-PAGE and autoradiography. Filamin-A, filamin-B, filamin-B_var-1 as well as filamin-C containing repeats 19-24 bind to GST-myotilin but not to GST alone (B). Filamin-A, filamin-B, filamin-B_var-1 as well as filamin-C containing repeats 19-24 bind to FATZ-1 but not to GST alone (C). The grouping of images was arranged from two different gels in B and in C. Note that filamin-B in the presence of FATZ-1 showed a tendency to proteolytic degradation under the conditions of the GST pull down experiments. Molecular mass markers are indicated in kDa.