IgA Fc receptor (FcalphaR) cross-linking recruits tyrosine kinases, phosphoinositide kinases and serine/threonine kinases to glycolipid rafts

Biochem J. 2002 Jun 1;364(Pt 2):517-25. doi: 10.1042/BJ20011696.

Abstract

The human IgA Fc receptor (FcalphaR, CD89) triggers several important physiological functions, including phagocytosis, NADPH oxidase activation and antigen presentation. Efforts are underway to delineate FcalphaR signal-transduction pathways that control these functions. In a previous study, we demonstrated that cross-linking of FcalphaR increased its partitioning into membrane glycolipid rafts and was accompanied by gamma-chain-dependent recruitment and phosphorylation of the tyrosine kinases Lck/Yes-related novel protein tyrosine kinase (Lyn) and Bruton's tyrosine kinase (Btk). Here we have performed a more extensive characterization of signalling effectors recruited to rafts on FcalphaR cross-linking. We demonstrate that in addition to tyrosine kinases Lyn and Btk, FcalphaR cross-linking also recruits B-lymphocyte kinase (Blk) and spleen tyrosine kinase (Syk) to rafts. We show recruitment of phosphoinositide kinases, including 3-phosphoinositide 3-kinase and phospholipase Cgamma2, and serine/threonine kinases such as protein kinase C (PKC) alpha, PKCepsilon, and protein kinase B (PKB) alpha. This suggests that lipid rafts serve as sites for FcalphaR-triggered recruitment of multiple classes of signalling effectors. We further demonstrate that tyrosine kinases and PKCalpha have a sustained association with rafts, whereas phosphoinositide 3-kinase and its downstream effectors have a transient association with rafts. This is consistent with temporally regulated divergence of FcalphaR signalling pathways in rafts. Furthermore, we suggest the spatial separation of signalling effectors by transport of phosphoinositide 3-kinase, phosphoinositide-dependent kinase 1, PKBalpha and PKCepsilon to endocytic compartments containing internalized FcalphaR.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 1-Phosphatidylinositol 4-Kinase / antagonists & inhibitors
  • 1-Phosphatidylinositol 4-Kinase / metabolism*
  • Cross-Linking Reagents / metabolism*
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme Inhibitors / pharmacology
  • Glycolipids / metabolism*
  • Phosphorylation
  • Protein Serine-Threonine Kinases / antagonists & inhibitors
  • Protein Serine-Threonine Kinases / metabolism*
  • Protein-Tyrosine Kinases / antagonists & inhibitors
  • Protein-Tyrosine Kinases / metabolism*
  • Receptors, Fc / metabolism*
  • Signal Transduction

Substances

  • Cross-Linking Reagents
  • Enzyme Inhibitors
  • Glycolipids
  • IgA receptor
  • Receptors, Fc
  • 1-Phosphatidylinositol 4-Kinase
  • Protein-Tyrosine Kinases
  • Protein Serine-Threonine Kinases