Interactions of tensin with actin and identification of its three distinct actin-binding domains

Su Hao Lo, Paul A. Janmey, John H. Hartwig, Lan Bo Chen

Research output: Contribution to journalArticle

121 Scopus citations

Abstract

Tensin, a 200-kD phosphoprotein of focal contacts, contains sequence homologies to Src (SH2 domain), and several actin-binding proteins. These features suggest that tensin may link the cell membrane to the cytoskeleton and respond directly to tyrosine kinase signalling pathways. Here we identify three distinct actin-binding domains within tensin. Recombinant tensin purified after overexpression by a baculovirus system binds to actin filaments with K(d) = 0.1 μM, cross-links actin filaments at a molar ratio of 1:10 (tensin/actin), and retards actin assembly by barbed end capping with K(d) = 20 nM. Tensin fragments were constructed and expressed as fusion proteins to map domains having these activities. Three regions from tensin interact with actin: two regions composed of amino acids 1 to 263 and 263 to 463, cosediment with F-actin but do not alter the kinetics of actin assembly; a region composed of amino acids 888-989, with sequence homology to insertin, retards actin polymerization. A claw-shaped tensin dimer would have six potential actin-binding sites and could embrace the ends of two actin filaments at focal contacts.

Original languageEnglish (US)
Pages (from-to)1067-1075
Number of pages9
JournalJournal of Cell Biology
Volume125
Issue number5
DOIs
StatePublished - Jun 1994
Externally publishedYes

ASJC Scopus subject areas

  • Cell Biology

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