[Endocytosis and receptors: molecular and physiological aspects]

One of the functions of the proximal tubule cells is to internalize and degrade proteins that have not been retained by the glomerulus. The magnitude of the amounts of protein reabsorbed (several hundreds of milligrams per day) imply specific structures that favor endocytosis and recycling of plasma membrane components as well as the expression of specific molecules that play a role in the endocytic traffic and/or act as multiligand receptors. In this study we review recent data that link 2 high molecular weight glycoproteins, gp330/megalin (600 kDa) and gp280 (460 kDa) to the endolytic process in proximal tubule cells.