title: The SH3 domain-containing adaptor HIP-55 mediates c-Jun N-terminal kinase activation in T cell receptor signaling.
abstract: HIP-55 (hematopoietic progenitor kinase 1 (HPK1)-interacting protein of 55 kDa, also called SH3P7 and mAbp1) is a novel SH3 domain-containing protein. HIP-55 binds to actin filaments both in vitro and in vivo. HIP-55 activates HPK1 and c-Jun N-terminal kinase (JNK), which are two important lymphocyte signaling molecules. Until now, the regulation and function of HIP-55 in T cell receptor (TCR) signaling were unknown. We found that HIP-55 was recruited to glycolipid-enriched microdomains upon TCR stimulation, which indicates that HIP-55 is regulated by TCR signaling. HIP-55 interacted with ZAP-70, a critical protein-tyrosine kinase in TCR signaling, and this interaction was induced by TCR signaling. ZAP-70 phosphorylated HIP-55 at Tyr-334 and Tyr-344 in vitro and in vivo, and the HIP-55 mutant (Y334F/Y344F) was not tyrosine-phosphorylated in stimulated T cells. To study its function in T cell activation, HIP-55-deficient Jurkat T cells were established using the RNA interference approach. In the HIP-55-deficient cells, TCR (but not UV)-stimulated JNK activation was decreased. Furthermore, the activation of HPK1, a known JNK upstream activator and HIP-55-interacting protein, was also decreased in the HIP-55-deficient cells. Our data reveal the regulation of HIP-55 during TCR signaling, and using a genetic approach, we demonstrate for the first time that HIP-55 plays a functional role in TCR signaling.
authors.affiliation: Department of Immunology, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: Jin
authors.initials: J
authors.lastname: Han
authors.forename: Rajashree
authors.initials: R
authors.lastname: Kori
authors.forename: Jr-Wen
authors.initials: JW
authors.lastname: Shui
authors.forename: Yi-Rong
authors.initials: YR
authors.lastname: Chen
authors.forename: Zhengbin
authors.initials: Z
authors.lastname: Yao
authors.forename: Tse-Hua
authors.initials: TH
authors.lastname: Tan
mesh_terms: D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D019169:Jurkat Cells; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism; D014162:Transfection; D014443:Tyrosine / Q000737:chemistry / Q000378:metabolism; D014466:Ultraviolet Rays; D051746:ZAP-70 Protein-Tyrosine Kinase; D018909:src Homology Domains
chemical_list: D002352:Carrier Proteins; D011948:Receptors, Antigen, T-Cell; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases