A novel recognition system for MHC class I molecules constituted by PIR.
The paired immunoglobulin (Ig)-like receptors (PIRs) represent a typical receptor pair of the Ig-like receptor family in which various combinations of ligand-receptor interaction provide a positive and negative regulation of immune cells, thus enabling those cells to respond properly to extrinsic stimuli. Activating PIR-A and inhibitory PIR-B are expressed in a wide range of cells in the murine immune system, such as B cells, mast cells, macrophages, and dendritic cells, mostly in a pair-wise fashion. PIRs bind to MHC class I molecules expressed ubiquitously on hematopoietic as well as nonhematopoietic cells. The unbalanced binding of PIR-A and PIR-B to MHC class I molecules may lead to the perturbation of cell development, regulation, and function as observed in PIR-B-deficient mice. Thus, PIR-A and PIR-B are indispensable for the regulation of cellular signaling and important for homeostasis of the immune system.
Takai
Toshiyuki
T
Department of Experimental Immunology and CREST Program of the Japan Science and Technology Agency, Institute of Development, Aging, and Cancer, Tohoku University, Sendai 980-8575, Japan.
D000818:Animals; D016207:Cytokines / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D025461:Feedback, Physiological; D005805:Genes, MHC Class I / Q000276:immunology*; D006706:Homeostasis; D006801:Humans; D007107:Immune System / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D008213:Lymphocyte Activation; D008262:Macrophage Activation; D051379:Mice; D011485:Protein Binding; D011971:Receptors, Immunologic / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction; D014181:Transplantation Immunology
D016207:Cytokines; C105948:Pira1 protein, mouse; C105949:Pirb protein, mouse; D011971:Receptors, Immunologic