PLCE1 regulates the migration, proliferation, and differentiation of podocytes

PLCE1 encodes phospholipase C epsilon, and its mutations cause recessive nephrotic syndrome. However, the mechanisms by which PLCE1 mutations result in defects associated with glomerular function are not clear. To address this, we investigated the function of PLCE1 in podocytes called glomerular epithelial cells, where the pathogenesis of nephrotic syndrome converges. PLCE1 colocalized with Rho GTPases in glomeruli. Further, it interacted with Rho GTPases through the pleckstrin homology domain and Ras GTP-binding domains 1/2. Knockdown or knockout of PLCE1 in podocytes resulted in decreased levels of GTP-bound Rac1 and Cdc42, but not those of RhoA, and caused a reduction in cell migration. PLCE1 interacted with NCK2 but not with NCK1. Similar to the PLCE1 knockout, NCK2 knockout resulted in decreased podocyte migration. Knockout of PLCE1 reduced the EGF-induced activation of ERK and cell proliferation in podocytes, whereas knockout of NCK2 did not affect proliferation. Further, the knockout of PLCE1 also resulted in decreased expression of podocyte markers, including NEPH1, NPHS1, WT1, and SYNPO, upon differentiation, but the knockout of NCK2 did not affect the expression of these markers. Therefore, our findings demonstrate that PLCE1 regulates Rho GTPase activity and cell migration through interacting with NCK2 and that PLCE1 also plays a role in the proliferation and differentiation of podocytes, regardless of the presence of NCK2.