CUBN and membranoproliferative glomerulonephritis: Immune-mediated proteinuria has thus far been proposed to be induced by two different mechanisms including unspecific accumulation of immunoglobins (Igs) in glomerular capillary (i.e. membranoproliferative glomerulonephritis and systemic lupus nephritis) or binding of specific Igs to podocytes-associated targets leading to disruption and loss of podocytes (i.e. membranous nephropathy)2,3.