Phosphorylation of LRP1: regulation of transport and signal transduction.

Low-density lipoprotein receptor-related protein 1 (LRP1) is a member of the low-density lipoprotein receptor family. Members of this family were once thought to be involved exclusively in receptor-mediated uptake of extracellular molecules, including lipoproteins and proteases. This article reviews recent work that indicates that LRP1 is phosphorylated on both serine and tyrosine residues. Tyrosine-phosphorylated LRP1 is specifically associated with the cellular docking protein Shc. The results suggest that ligand internalization by LRP1 is regulated by phosphorylation. In addition, LRP1 is now, like several of its close relatives, implicated in signal transduction.