Immunoreceptor tyrosine-based activation motif (ITAM), a unique module linking antigen and Fc receptors to their signaling cascades.
Signal transduction by the T cell and B cell antigen receptors and by receptors for a variety of immunoglobulins' Fc region is strictly dependent on a receptor subunit cytoplasmic module termed immunoreceptor tyrosine-based activation motif (ITAM). This module exists in one or more copies in each of the receptor-associated signal-transducing molecules and it possesses two repeats of the consensus sequence Tyr-X-X-Leu/Ile spaced by six to eight amino acids. Receptor engagement is followed by a rapid and transient phosphorylation of tyrosine residues within their ITAMs, thereby creating temporary binding sites for Src homology 2 (SH2)-containing signaling molecules operating downstream of the activated receptor. The purpose of this review is to discuss recent findings on the functional role of ITAMs in antigen and Fc receptor-mediated signal transduction, with a particular emphasis on kinases operating upstream and downstream of the ITAMs.
Isakov
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Department of Microbiology and Immunology, Faculty of Health Sciences, and the Cancer Research Center, Ben Gurion University of the Negev, Beer Sheva, Israel.
D010766:Phosphorylation; D017459:Receptors, Amino Acid / Q000276:immunology / Q000378:metabolism*; D011947:Receptors, Antigen, B-Cell / Q000737:chemistry / Q000276:immunology / Q000502:physiology*; D011948:Receptors, Antigen, T-Cell / Q000737:chemistry / Q000276:immunology / Q000502:physiology*; D011961:Receptors, Fc / Q000737:chemistry / Q000276:immunology / Q000502:physiology*; D015398:Signal Transduction / Q000276:immunology / Q000502:physiology*; D019061:src-Family Kinases / Q000276:immunology / Q000502:physiology*
D017459:Receptors, Amino Acid; D011947:Receptors, Antigen, B-Cell; D011948:Receptors, Antigen, T-Cell; D011961:Receptors, Fc; C087659:tyrosine receptor; D019061:src-Family Kinases