Fig 1. Syn-3 co-immunoprecipitates (IP) distinct Ca_vs than Syn-1A in INS-1 cells.

Syn-3 (A) and Syn-1A (C) interactions with the indicated Ca_vα1 subunits (Ca_v1.2, Ca_v1.3, Ca_v2.3 and Ca_v2.2) and auxiliary subunits (α₂δ-1 and β3) and SNAP25 in INS-1 cells. Densitometric analysis of Syn-3 co-IP (B) and Syn-1A co-IP (D), expressed as percent recovery of total lysate inputs (which showed equal protein loading in S1 Fig), shows that high glucose (16.7 mM) plus GLP-1 (10 nM) increased the association of these syntaxins with the respective Ca_vs. Values are means±SEM, n = 3. *p<0.05, ***p<0.001, NS: not significant. As control (E) shows representative blots from five separate co-IP experiments with pre-immune IgG, which did not bring down syntaxins or Ca_vs (left lanes). Right lanes show the input lysates. All five experiments probed for the Ca_v α subunits and α₂δ-1, whereas β3, Syn-3 and Syn-1A were probed on two blots from separate experiments.