The Scaffolding Protein CG-NAP/AKAP450 Is a Critical Integrating Component of the LFA-1-Induced Signaling Complex in Migratory T Cells

• Published in: Journal of Immunology Vol. 175; no. 12; pp. 7811 - 7818
• Main Authors: El Homasany, Basma Salah El Din, Volkov, Yuri, Takahashi, Mikiko, Ono, Yoshitaka, Keryer, Guy, Delouvee, Annie, Looby, Eileen, Long, Aideen, Kelleher, Dermot
• Format: Journal Article
• Language: English
• Published: United States Am Assoc Immnol 15.12.2005
• Subjects: 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
• ISSN: 0022-1767; 1550-6606; 1365-2567
• DOI: 10.4049/jimmunol.175.12.7811

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.