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PIST (also known as GOPC), a trans-Golgi protein, was initially identified as interacting partner of GTPase TC10 and mainly involved in trafficking regulation of plasma membrane destined proteins. PIST is ubiquitously expressed in all tissue types whereas its neuronal isoform nPIST is exclusively found in whole brain preferentially in cerebellum, hippocampus, and cerebral cortex. It comprises of N-terminal coiled-coil domain and C-terminal PDZ domain. nPIST interacts with glutamate delta2 receptor (GluRĪ“2) and Beclin-1 in Purkinje cells. nPIST is known to regulate translocation of neuronal receptors. We are reporting nPIST as a novel actin binding protein. In silico modeling of nPIST reveals presence of a putative WH2-like domain having actin binding potential. Truncated fragments of nPIST were subjected to F-actin co-sedimentation assay. The in vitro experimental procedure unveiled that nPIST has multiple regions engaged in interaction with actin. The presence of several actin binding motifs makes nPIST proficient in stabilizing F-actin filaments in vitro. In vivo, nPIST causes abnormal accumulation of actin in the perinuclear region and disrupts golgi morphology when ectopically expressed. Studies show that actin network is required for proper positioning and maintenance of Golgi machinery. Till date few WH2 domain containing actin binding proteins have been reported to be linking actin cytoskeleton to vesicular trafficking regulation, and modeling of Golgi architecture. Our candidate protein nPIST might also be another WH2-like domain containing protein mediating cross-talk between actin cytoskeleton and vesicular trafficking machinery. |