Interaction of Tomo1 with Rab3A and Synapsin 1 is regulated by Cdk5. A, Western blot showing that IP of Tomo1 from hippocampal neuronal lysates coprecipitates Synapsin 1 (a, b isoforms) and Rab3A. B, IP with isotype-control rabbit IgG, to verify the specificity protein anti-Tomo1 coprecipitation, does not precipitate Tomo1, Rab3A, or Synapsin 1. C, Rab3A was cleared from lysate by IP with a Rab3A antibody (top blot, S is IP cleared supernatant). Subsequent IP of Tomo1 from the Rab3A cleared supernatant (S) shows no detectable pulldown (P) of Rab3A or Synapsin1 (bottom blot). Note supernatant (S) after the IP retained Synapsin 1a,b and low-level Rab3A immunoreactivity. D, Effect of CSA (50 μm) and Rosco (100 μm) pretreatment (30 m) and vehicle control on Tomo1 coprecipitation of Rab3A and Synapsin 1 from neuronal lysates. E, Averaged Tomo1 coprecipitation of Rab3A and Synapsin 1, as normalized to control, for each condition. *p < 0.05.