OSBP-related protein 4L promotes phospholipase C{beta}3 translocation from the nucleus to the plasma membrane in Jurkat T-cells [Signal Transduction] (Journal of Biological Chemistry)

Phosphoinositide phospholipases C (PLCs) are a family of eukaryotic intracellular enzymes with important roles in signal transduction. In addition to their location at the plasma membrane, PLCs also exist within the cell nucleus where they are stored. We previously demonstrated that OSBP-related protein 4L (ORP4L) anchors cluster of differentiation 3? (CD3?) to the heterotrimeric G protein subunit (G?q/11) to control PLC?3 relocation and activation. However, the underlying mechanism by which ORP4L facilitates PLC?3 translocation remains unknown. Here, using confocal immunofluorescence microscopy and coimmunoprecipitation assays, we report that ORP4L stimulates PLC?3 translocation from the nucleus to the plasma membrane in Jurkat T-cells in two steps. First, we found that ORP4L is required for the activation of Ras-related nuclear protein (RAN), a GTP-binding nuclear protein that binds to exportin 1 and eventually promotes the nuclear export of PLC?3. Second, we also observed that ORP4L interacts with vesicle-associated membrane protein-associated protein A (VAPA) through its two phenylalanines in an acidic tract (FFAT) motif. This complex enabled PLC?3 movement to the plasma membrane, indicating that PLC?3 translocation occurs in a VAPA-dependent manner. This study reveals detailed mechanistic insight into the role of ORP4L in PLC?3 redistribution from storage within the nucleus to the plasma membrane via RAN activation and interaction with VAPA in Jurkat T-cells.