Fig. 6. Effect of myc-tagged MyBP-C recombinant proteins on MyHC organization in transfected COS cells. COS cells were transiently transfected with full-length MyBP-C (A,E,I,M), C7-10 (B,F,J,N), C10 (C,G,K,O) and C1-9 (D,H,L,P) and analyzed by indirect immunofluorescence. Cells doubly transfected with MyHC are shown in E-P. Two days after transfection, the cells were fixed and immunoreacted with biotinylated anti-c-myc antibody, 9E10, and anti-myosin mAb F59. A-H show localization of the myc-tagged MyBP-C proteins. I-L reveal the expression and distribution of MyHC. The overlap of MyBP-Cs and MyHC is shown in M-P. All four MyBP-C recombinant proteins co-distributed with MyHC. Full-length MyBP-C, C7-10 and C10 induced cable formation when expressed with MyHC. By contrast, C1-9 did not form cables with MyHC.