Figure 1.

GAB1 is cleaved during CVB3 infection. A) Cleavage of endogenous GAB1 following CVB3 infection. HeLa cells were sham- or CVB3-infected at multiplicity of infections 10 for various time points as indicated. Cell lysates were collected and processed for Western blotting for detection of viral capsid protein VP1 and GAB1 protein expression (using an anti-GAB1 antibody targeting residues surrounding Tyr472 of human GAB1). The protein level of β-actin was examined as a loading control. B) Cleavage of exogenous GAB1 following CVB3 infection. HeLa cells were transiently transfected with a plasmid expressing N-terminal Flag-tagged GAB1 (3×Flag-GAB1) for 24 h, followed by CVB3 infection for different time points as indicated. Western blotting was performed to assess the protein levels of exogenous GAB1 (using anti-Flag antibody), VP1, and β-actin. Arrowheads indicate CVB3-induced GAB1 cleavage fragments. C) Schematic diagram of full-length GAB1 with various functional domains, the resulting cleavage fragments, and the regions that individual antibodies detected. Red arrows indicate 2 potential cleavage sites. pi, post infection.