SMPDL3B and focal segmental glomerulosclerosis: In FSGS, increased circulating soluble urokinase plasminogen activator receptor (suPAR) together with low or absent SMPDL3b expression were demonstrated to result in αVβ3 integrins activation, increased Src phosphorylation, and enhancement of Rac1 activity, which ultimately induced a migratory podocyte phenotype.