The function of PTB domain proteins.
Phosphotyrosine binding (PTB) domains have been identified in a large number of proteins. In proteins like Shc and IRS-1, the PTB domain binds in a phosphotyrosine-dependent fashion to peptides that form a b turn. In these proteins, PTB domains play an important role in signal transduction by growth factor receptors. However, in several other proteins, the PTB domains have been found to participate in phosphotyrosine-independent interactions. The X11 family of proteins contains a PTB domain that binds peptides in a phosphotyrosine-independent fashion. The homologue of X11 in C. elegans is the lin-10 gene, a gene crucial for receptor targeting to the basolateral surface of body wall epithelia. The X11/Lin-10 proteins are found in a complex with two other proteins, Lin-2 and Lin-7, which have also been implicated in basolateral targeting in worm epithelia. This protein complex is also likely to be important in the targeting of cell surface proteins in mammalian neurons and epithelia. The ability of the PTB domain to bind peptides in a phosphotyrosine-dependent and -independent fashion allows this domain to be involved in diverse cellular functions.
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Department of Internal Medicine and Biological Chemistry, Howard HughesMedical Institute, University of Michigan Medical School, Ann Arbor 48109-0650, USA. bmargoli@uv1.im.med.umich.edu
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D000818:Animals; D029742:Caenorhabditis elegans Proteins; D004847:Epithelial Cells / Q000737:chemistry / Q000378:metabolism*; D015801:Helminth Proteins / Q000737:chemistry / Q000378:metabolism; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000378:metabolism; D019000:Phosphotyrosine / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011506:Proteins; D018909:src Homology Domains / Q000502:physiology*
D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D011506:Proteins; C064105:lin-10 protein, C elegans; D019000:Phosphotyrosine