Megalin and its associated molecules in proximal tubule epithelial cells (PTECs). Among the various molecules present on the apical membrane of PTECs, megalin plays the central role in receptor-mediated endocytosis. Megalin also functions cooperatively with other membrane proteins, such as the cubilin-amnionless complex (CUBAM), NHE3, and ClC5. NaPi-IIa is responsible for the renal uptake of Pi, whereas NHE3 and ClC5 are involved in further processing of endocytosed proteins. The neonatal receptor FcRn might be involved in the uptake and transcytosis of filtered albumin. A number of intracellular adaptor proteins, including ARH, Dab2, and GIPC, are involved in megalin trafficking. Reproduced with permission from [14]. Copyright 2011 Nova Science Publishers Inc.