The scaffolding protein CG-NAP/AKAP450 is a critical integrating component of the LFA-1-induced signaling complex in migratory T cells

J Immunol. 2005 Dec 15;175(12):7811-8. doi: 10.4049/jimmunol.175.12.7811.

Abstract

T cell migration represents a complex highly coordinated process involving participation of surface receptor/ligand interactions, cytoskeletal rearrangements, and phosphorylation-dependent signaling cascades. Members of the A-kinase anchoring protein (AKAP) family of giant scaffolding proteins can assemble and compartmentalize multiple signaling and structural molecules thereby providing a platform for their targeted positioning and efficient interactions. We characterize here the expression, intracellular distribution, and functional role of the scaffolding protein CG-NAP (centrosome and Golgi localized protein kinase N-associated protein)/AKAP450 in the process of active T cell motility induced via LFA-1 integrins. This protein is predominantly localized at the centrosome and Golgi complex. T cell locomotion triggered by LFA-1 ligation induces redistribution of CG-NAP/AKAP450 along microtubules in trailing cell extensions. Using an original in situ immunoprecipitation approach, we show that CG-NAP/AKAP450 is physically associated with LFA-1 in the multimolecular signaling complex also including tubulin and the protein kinase C beta and delta isoenzymes. CG-NAP/AKAP450 recruitment to this complex was specific for the T cells migrating on LFA-1 ligands, but not on the beta(1) integrin ligand fibronectin. Using the GFP-tagged C-terminal CG-NAP/AKAP450 construct, we demonstrate that expression of the intact CG-NAP/AKAP450 and its recruitment to the LFA-1-associated multimolecular complex is critically important for polarization and migration of T cells induced by this integrin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A Kinase Anchor Proteins
  • Adaptor Proteins, Signal Transducing / metabolism
  • Adaptor Proteins, Signal Transducing / physiology*
  • Cell Line, Tumor
  • Cells, Cultured
  • Centrosome / metabolism
  • Chemotaxis, Leukocyte*
  • Cytoskeletal Proteins / metabolism
  • Cytoskeletal Proteins / physiology*
  • Golgi Apparatus / metabolism
  • Humans
  • Lymphocyte Function-Associated Antigen-1 / metabolism
  • Lymphocyte Function-Associated Antigen-1 / physiology*
  • Microtubules / metabolism
  • Multiprotein Complexes / physiology
  • Signal Transduction
  • T-Lymphocytes / cytology
  • T-Lymphocytes / physiology

Substances

  • A Kinase Anchor Proteins
  • AKAP9 protein, human
  • Adaptor Proteins, Signal Transducing
  • Cytoskeletal Proteins
  • Lymphocyte Function-Associated Antigen-1
  • Multiprotein Complexes