Palmitoylation is required for Sept8‐204 and Sept5 to form vesicle‐like structure and colocalize with synaptophysin

Abstract Sept8 is a vesicle associated protein and there are two typical transcriptional variants (Sept8‐204 and Sept8‐201) expressed in mice brain. Interestingly, the coexpression of Sept8‐204/Sept5 induces the formation of small sized vesicle‐like structure, while that of the Sept8‐201/Sept5 produces large puncta. Sept8 is previously shown to be palmitoylated. Here it was further revealed that protein palmitoylation is required for Sept8‐204/Sept5 to maintain small sized vesicle‐like structure and colocalize with synaptophysin, since either the expression of nonpalmitoylated Sept8‐204 mutant (Sept8‐204‐3CA) or inhibiting Sept8‐204 palmitoylation by 2‐BP with Sept5 produces large puncta, which barely colocalizes with synaptophysin (SYP). Moreover, it was shown that the dynamic palmitoylation of Sept8‐204 is controlled by ZDHHC17 and PPT1, loss of ZDHHC17 decreases Sept8‐204 palmitoylation and induces large puncta, while loss of PPT1 increases Sept8‐204 palmitoylation and induces small sized vesicle‐like structure. Together, these findings suggest that palmitoylation is essential for the maintenance of the small sized vesicle‐like structure for Sept8‐204/Sept5, and may hint their important roles in synaptic functions.