The N-terminal domains of tensin and auxilin are phosphatase homologues.
Tensin, an actin filament capping protein, and auxilin, a component of receptor-mediated endocytosis, are known to have 350 residue regions of significant sequence similarity near their N-termini (Schröder et al., 1995, Eur J Biochem 228:297-304). Here we demonstrate that these regions are homologous, not only to each other, but also to the catalytic domain of a putative protein tyrosine phosphatase (PTP) from Saccharomyces cerevisiae and to other PTPs. We propose that the PTP-like portion of the homology region of tensin and auxilin represents a distinct domain. A detailed sequence comparison indicates that the PTP-like domain in tensin is unlikely to exhibit phosphatase activity, whereas in auxilin it may possess a different phosphatase specificity from tyrosine phosphatases. It is probable that the PTP-like domains in tensin and auxilin mediate binding interactions with phosphorylated polypeptides; they may therefore represent members of a distinct class of phosphopeptide recognition domain.
Haynie
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Oxford Centre for Molecular Sciences, University of Oxford, United Kingdom.
Ponting
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D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002645:Chickens; D008840:Microfilament Proteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics*; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics*; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics*; D016415:Sequence Alignment; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D000070876:Tensins
D033942:Adaptor Proteins, Vesicular Transport; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D000070876:Tensins; D010744:Phosphoric Monoester Hydrolases