Figure 12.

The syntaxin 17 complex(es) contains five vesicle-trafficking proteins. (A) Rat testis membrane extract was fractionated by centrifugation through an 11–35% glycerol velocity gradient, and sequential fractions were analyzed by electrophoresis and immunoblotting with antibodies against syntaxin 17. Note that the entire pool of syntaxin 17 is present in an oligomeric complex(es). (B) Rat testis membranes were isolated and solubilized with 1% Triton X-100. The solubilized membranes were incubated with protein G–Sepharose beads loaded with either mouse monoclonal anti-syntaxin 17 antibody or with nonspecific mouse IgG. After the binding step, the beads were washed, eluted with SDS protein sample dye, resolved by SDS-PAGE, and visualized with Coomassie blue. The indicated bands were excised from the gel, digested with trypsin, and analyzed by microsequencing and mass spectrometry. The labels to the right indicate the identities of the precipitated proteins.