title: Activated Cdc42-associated kinase 1 (ACK1) binds the sterile α motif (SAM) domain of the adaptor SLP-76 and phosphorylates proximal tyrosines.
abstract: The adaptor protein Src homology 2 domain-containing leukocyte phosphoprotein of 76 kDa (SLP-76) plays a crucial role in T cell activation by linking antigen receptor (T cell receptor, TCR) signals to downstream pathways. At its N terminus, SLP-76 has three key tyrosines (Tyr-113, Tyr-128, and Tyr-145, "3Y") as well as a sterile α motif (SAM) domain whose function is unclear. We showed previously that the SAM domain has two binding regions that mediate dimer and oligomer formation. In this study, we have identified SAM domain-carrying non-receptor tyrosine kinase, activated Cdc42-associated tyrosine kinase 1 (ACK1; also known as Tnk2, tyrosine kinase non-receptor 2) as a novel binding partner of SLP-76. Co-precipitation, laser-scanning confocal microscopy, andin situproximity analysis confirmed the binding of ACK1 to SLP-76. Further, the interaction was induced in response to the anti-TCR ligation and abrogated by the deletion of SLP-76 SAM domain (ΔSAM) or mutation of Tyr-113, Tyr-128, and Tyr-145 to phenylalanine (3Y3F). ACK1 induced phosphorylation of the SLP-76 N-terminal tyrosines (3Y) dependent on the SAM domain. Further, ACK1 promoted calcium flux and NFAT-AP1 promoter activity and decreased the motility of murine CD4+primary T cells on ICAM-1-coated plates, an event reversed by a small molecule inhibitor of ACK1 (AIM-100). These findings identify ACK1 as a novel SLP-76-associated protein-tyrosine kinase that modulates early activation events in T cells.
authors.affiliation: From the Cell Signaling Section, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom, youg_thaker@hms.harvard.edu.
authors.forename: Youg R
authors.initials: YR
authors.lastname: Thaker
authors.affiliation: From the Cell Signaling Section, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom.
authors.forename: Asha
authors.initials: A
authors.lastname: Recino
authors.affiliation: the Department of Obstetrics and Gynecology, School of Medicine, J. W. Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
authors.forename: Monika
authors.initials: M
authors.lastname: Raab
authors.affiliation: the School of Biological Science, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, United Kingdom.
authors.forename: Asma
authors.initials: A
authors.lastname: Jabeen
authors.affiliation: From the Cell Signaling Section, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom.
authors.forename: Maja
authors.initials: M
authors.lastname: Wallberg
authors.affiliation: the School of Biological Science, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, United Kingdom.
authors.forename: Nelson
authors.initials: N
authors.lastname: Fernandez
authors.affiliation: From the Cell Signaling Section, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, United Kingdom.|the Division of Immunology-Oncology Research Center Maisonneuve-Rosemont Hospital, Montreal, Quebec H1T 2M4, Canada, and.|the Département de Medicine, Université de Montréal, Montreal, Quebec H3C 3J7, Canada.
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Rudd
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D020816:Amino Acid Motifs; D019943:Amino Acid Substitution; D000818:Animals; D006801:Humans; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000502:physiology*; D051379:Mice; D020125:Mutation, Missense; D010750:Phosphoproteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology; D000072417:Protein Domains; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D014443:Tyrosine
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D010750:Phosphoproteins; D011948:Receptors, Antigen, T-Cell; C092947:SLP-76 signal Transducing adaptor proteins; D014443:Tyrosine; C498594:Tnk2 protein, mouse; D011505:Protein-Tyrosine Kinases; C403262:TNK2 protein, human
keywords: T cell; cell signaling; cluster of differentiation 4 (CD4); immunology; non-receptor tyrosine kinase (nRTK); protein phosphorylation; sterile α motif (SAM)