Figure 9.

Schematic diagram of AP dysregulation caused by the C3 I734T mutation leading to glomerular C3 deposits. Generated C3b and its cleavage fragments from the capillary lumen (CL) cross the fenestrated glomerular endothelium (GEc) and reach the subendothelial space and the mesangium (M) in the vicinity of mesangial cells (Mc), where C3b is only partially regulated by FH, leading to the accumulation of C3b and iC3b in these areas. C3b and iC3b fragments cross the GBM toward the subepithelial space. They cannot be appropriately regulated by CR1 expressed on the foot podocytes, resulting in iC3b/C3d accumulation (humps). US, urinary space.