Cutting edge: signal-regulatory protein beta 1 is a DAP12-associated activating receptor expressed in myeloid cells.
Signal-regulatory proteins (SIRPs) are cell-surface glycoproteins expressed on myeloid and neural cells that have been shown to recruit SH2 domain-containing protein phosphatase 1 (SHP-1) and SHP-2 and to regulate receptor tyrosine kinase-coupled signaling. One SIRP of unknown function, designated SIRP beta 1, contains a short cytoplasmic domain that lacks sequence motifs capable of recruiting SHP-1 and SHP-2. Using a SIRP-specific mAb, we show that SIRP beta 1 is expressed in monocytes and dendritic cells and associates with the signal transduction molecule DAP12. SIRP beta 1/DAP12 complex formation was required for efficient cell-surface expression of SIRP beta 1. Stimulation of this complex induced tyrosine phosphorylation, mitogen-activated protein kinase activation, and cellular activation. Thus, SIRP beta 1 is a new DAP12-associated receptor involved in the activation of myeloid cells.
Pubmed ID: 10604985 RIS Download
Adaptor Proteins, Signal Transducing | Animals | Antigens, Differentiation | Cell Line | Dendritic Cells | Humans | Jurkat Cells | Membrane Glycoproteins | Membrane Proteins | Mice | Mice, Inbred BALB C | Mitogen-Activated Protein Kinase 1 | Mitogen-Activated Protein Kinase 3 | Mitogen-Activated Protein Kinases | Molecular Weight | Monocytes | Neural Cell Adhesion Molecule L1 | Neural Cell Adhesion Molecules | Phosphorylation | Receptors, Cell Surface | Receptors, Immunologic | Signal Transduction | U937 Cells