SFPQ preferentially binds to KIF5A/KLC1 in DRG sensory neurons. (A) Schematic of domains for kinesin heavy chain (KHC) and KLC and their interacting region between the coiled coil of KHC and with the heptad repeat of KLC. (B) PRM-based quantification of KIF5A, KIF5B, and KIF5C in SFPQ immunoprecipitations. Error bars represent SD, n = 3; ****P < 0.001; 95% CIs for the difference in means (KIF5A; KIF5B: 47.0-64.3%; and KIF5A; KIF5C: 65.7-77.2%), Welch two-sample t test. (C) PRM-based quantification of KLC1 and KLC2 in SFPQ immunoprecipitations. Error bars represent SD, n = 3; ***P < 0.05, 95% CI for the difference in means (KLC1-KLC2: 30.9-66.7%), Welch two-sample t test. (D) IP of endogenous SFPQ from DRG sensory neuron protein lysate and blotted against endogenous KIF5A, KIF5B, and KIF5C. IgG serves as control IP, input represents 3% of 0.5 mg of protein lysate used for SFPQ IP, and total elute from the bead was run on the gel. (E) Quantification of pull down in D relative to input. ****P < 0.0001 by two-way ANOVA; n = 3 independent IPs; data represent mean ± SEM. (F) IP of endogenous SFPQ from DRG sensory neuron protein lysate and blotted against endogenous KLC1 and KLC2. IgG serves as control IP, input represents 3% of 0.5 mg of protein lysate used for SFPQ IP, and total elute from the bead was run on the gel. (G) Schematic representation of DRG sensory neurons grown in compartmented Campenot culture for preparing protein lysates for Western blot. (H and I) Western blot of DRG neuron lysates of CB and distal axon (DA) prepared from compartmented Campenot cultures probed against endogenous KIF5 motors (H) and KLCs (I); actin serves as loading control for H.