GPI-anchored uPAR requires Endo180 for rapid directional sensing during chemotaxis

J Cell Biol. 2003 Sep 1;162(5):789-94. doi: 10.1083/jcb.200302124.

Abstract

Urokinase-type plasminogen activator (uPA) and its receptor (uPAR) play an important role in cell guidance and chemotaxis during normal and pathological events. uPAR is GPI-anchored and the mechanism by which it transmits intracellular polarity cues across the plasma membrane during directional sensing has not been elucidated. The constitutively recycling endocytic receptor Endo180 forms a trimolecular complex with uPAR in the presence of uPA, hence its alternate name uPAR-associated protein. Here, we demonstrate that Endo180 is a general promoter of random cell migration and has a more specific function in cell chemotaxis up a uPA gradient. Endo180 expression was demonstrated to enhance uPA-mediated filopodia production and promote rapid activation of Cdc42 and Rac. Expression of a noninternalizing Endo180 mutant revealed that promotion of random cell migration requires receptor endocytosis, whereas the chemotactic response to uPA does not. From these studies, we conclude that Endo180 is a crucial link between uPA-uPAR and setting of the internal cellular compass.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line, Tumor
  • Chemotaxis / physiology*
  • Enzyme Activation
  • Glycosylphosphatidylinositols / metabolism*
  • Humans
  • Membrane Glycoproteins / metabolism
  • Mitogen-Activated Protein Kinases / metabolism
  • Protein Serine-Threonine Kinases*
  • Proto-Oncogene Proteins / metabolism
  • Proto-Oncogene Proteins c-akt
  • Pseudopodia / metabolism
  • Receptors, Cell Surface / metabolism*
  • Receptors, Mitogen / metabolism*
  • Receptors, Urokinase Plasminogen Activator
  • Urokinase-Type Plasminogen Activator / metabolism
  • cdc42 GTP-Binding Protein / metabolism
  • rac GTP-Binding Proteins / metabolism

Substances

  • Endo180
  • Glycosylphosphatidylinositols
  • Membrane Glycoproteins
  • PLAUR protein, human
  • Proto-Oncogene Proteins
  • Receptors, Cell Surface
  • Receptors, Mitogen
  • Receptors, Urokinase Plasminogen Activator
  • Protein Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt
  • Mitogen-Activated Protein Kinases
  • Urokinase-Type Plasminogen Activator
  • cdc42 GTP-Binding Protein
  • rac GTP-Binding Proteins