9.A.49 The Prenylated Rab Acceptor Protein 1 (PRA1) Family
PRA1 domain family, member 2 (PRAF2) is a 19-kDa protein with a prenylated Rab acceptor 1 (PRA1) motif and four TMSs. PRAF2 is highly expressed in the brain and serves as a candidate prognostic marker in neuroblastoma (NB). PRAF2 is related to proteins PRAF1 (PRA1, prenylin, Yip3) and PRAF3 (GTRAP3-18, JWA, Arl6-IP5), both of which are enriched in the brain and implicated in cellular transport and endo/exocytic vesicle trafficking. The distribution and localization of PRAF2 in the mature human brain revealed that in the human cerebellum, the PRAF2 protein is strongly expressed in Purkinje cells and, more moderately, in cells of the molecular and the granular layers (Koomoa et al. 2008; ). In the cerebral cortex, hippocampus and lateral ventricles, PRAF2 can be detected in neuronal cells but not non-neuronal cells. PRAF2 is enriched in synaptic vesicles prepared from rat brains. The expression of PRAF2 in specific regions of the brain including synaptic vesicles suggest a physiological function in participatioin of multiple aspects of synaptic vesicle maturation, transport and signal transmission. Di-arginine and FFAT-like motifs retain a subpopulation of PRA1 at ER-mitochondria membrane contact sites, suggesting that it has a functional role within the ER (Abu Irqeba and Ogilvie 2020).