Hematopoietic progenitor kinase 1 associates physically and functionally with the adaptor proteins B cell linker protein and SLP-76 in lymphocytes.
B cell linker protein (BLNK) is a SLP-76-related adaptor protein essential for signal transduction from the BCR. To identify components of BLNK-associated signaling pathways, we performed a phosphorylation-dependent yeast two-hybrid analysis using BLNK probes. Here we report that the serine/threonine kinase hematopoietic progenitor kinase 1 (HPK1), which is activated upon antigen-receptor stimulation and which has been implicated in the regulation of MAP kinase pathways, interacts physically and functionally with BLNK in B cells and with SLP-76 in T cells. This interaction requires Tyr(379) of HPK1 and the Src homology 2 (SH2) domain of BLNK/SLP-76. Via homology modeling, we defined a consensus binding site within ligands for SLP family SH2 domains. We further demonstrate that the SH2 domain of SLP-76 participates in the regulation of AP-1 and NFAT activation in response to T cell receptor (TCR) stimulation and that HPK1 inhibits AP-1 activation in a manner partially dependent on its interaction with SLP-76. Our data are consistent with a model in which full activation of HPK1 requires its own phosphorylation on tyrosine and subsequent interaction with adaptors of the SLP family, providing a mechanistic basis for the integration of this kinase into antigen receptor signaling cascades.
Sauer
K
K
Department of Immunology and Rheumatology and Department of Molecular Systems, Merck Research Laboratories, Rahway, New Jersey 07065, USA. Karsten_Sauer@Merck.com
Liou
J
J
Singh
S B
SB
Yablonski
D
D
Weiss
A
A
Perlmutter
R M
RM
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D018076:DNA, Complementary / Q000378:metabolism; D019992:Databases as Topic; D004789:Enzyme Activation; D006801:Humans; D015151:Immunoblotting; D019169:Jurkat Cells; D008214:Lymphocytes / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010750:Phosphoproteins / Q000378:metabolism*; D011233:Precipitin Tests; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism* / Q000502:physiology*; D017434:Protein Structure, Tertiary; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D015854:Up-Regulation; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; C113939:B cell linker protein; D002352:Carrier Proteins; D018076:DNA, Complementary; D010750:Phosphoproteins; C092947:SLP-76 signal Transducing adaptor proteins; D018808:Transcription Factor AP-1; C102102:hematopoietic progenitor kinase 1; D017346:Protein Serine-Threonine Kinases