Phospholipid phosphatase related 1 (PLPPR1) increases cell adhesion through modulation of Rac1 activity

Phospholipid Phosphatase-Related Protein Type 1 (PLPPR1) is a six-transmembrane protein that belongs to the family of plasticity-related gene proteins, which is a novel brain-specific subclass of the lipid phosphate phosphatase superfamily. PLPPR1-5 have prominent roles in synapse formation and axonal pathfinding. We found that PLPPR1 overexpression in the mouse neuroblastoma cell line (Neuro2a) results in increase in cell adhesion and reduced cell migration. During migration, these cells leave behind long fibrous looking extensions of the plasma membrane causing a peculiar phenotype. Cells expressing PLPPR1 showed decreased actin turnover and decreased disassembly of focal adhesions. PLPPR1 also reduced active Rac1, and expressing dominant negative Rac1 produced a similar phenotype to overexpression of PLPPR1. The PLPPR1-induced phenotype of long fibers was reversed by introducing constitutively active Rac1. In summary, we show that PLPPR1 decreases active Rac1 levels that leads to cascade of events which increases cell adhesion.