Fig 1: STAM1 deletion causes reduced expression of VTI1A and VAMP2. (A) Quantitation and representative immunoblots showing levels of SNAP25 (p = 0.7208), SV2A (p = 0.6292), SYN1 (p = 0.9335), SYP (p = 0.4278), SYT1 (p = 0.7787), STX1A (p = 0.2887), STX1B (p = 0.1477), STX6 (p = 0.7953), VAMP1 (p = 0.1282), VAMP2 (p = 0.0247) and VTI1A (p = 0.0049) in the spinal cords of 3-month-old wild-type (wt) and Stam1KO mice. When multiple known isoforms of a protein were detected, an asterisk was placed next to immunoblot to indicate the protein bands that were quantitated. ACTB was used as a loading control. (B) Representative L4/5 spinal cord segments from 3-month-old wt and Stam1KO mice stained for VTI1A and DAPI. (C) Cumulative frequency plot showing the size distribution of VTI1A puncta in motor neurons of 3-month-old wt and Stam1KO mice. The Kolmogorov-Smirnov test was used to determine significance. Quantitation of average (D) size (p < 0.0001), (E) fluorescence intensity (p = 0.0004) and (F) number (p = 0.4337) of VTI1A puncta in L4/5 spinal cord segments from 3-month-old wt and Stam1KO mice. (G) Average area of motor neurons in 3-month-old wt and Stam1KO mice (p = 0.7609). (H) Immunoblot analysis of proteins that co-immunoprecipitated with STAM1 in spinal cord lysates from 1-month-old wild-type mice. Lanes represent input lysate, proteins that did not bind to the beads, and proteins that were captured by the STAM1 antibody bead complex. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.