Sorting Nexin 32 ‐ a navigator with multifaceted roles in intracellular trafficking

Sorting nexin family of proteins characterized by the presence of a PX domain, gained its popularity owing to its multifaceted functional implications in the vesicular trafficking process. SNX32 is a PX‐BAR family member, whose physiological relevance is not much explored. In spite of having a BAR domain, the inability to form membrane tubulation and 70% sequence similarity to its close homologue SNX6 led to a prognosis of functional overlap and further naming it as SNX6b. However, the expression of SNX32 in addition to SNX6 indicates its specific necessity. Here, we demonstrate that SNX32 shows an ability to form heterodimers via its BAR domain, which was further investigated to understand its functional importance in vesicular trafficking. Relatedly utilising RNAi mediated down regulation of SNX32 we show that the cargo retrieval of CIMPR to TGN as well as Transferrin to Rab11 Positive recycling endosomes were perturbed. The cargo cotransport with SNX heterodimers as well as the difference in PhosphatidylInositol preference of individual SNXs suggests the importance of such an association. Further, the predominant expression of SNX32 in the brain signifies that it might have other tissue specific functionalities. Our initial results in the mouse neuroblastoma cell line suggest that SNX32 is important for the formation of neurites and thus control critical cellular events in the brain.