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Cargo binding induces dimerization of myosin VI.

ABSTRACT: Although myosin VI has properties that would allow it to function optimally as a dimer, full-length myosin VI exists as a monomer in isolation. Based on the ability of myosin VI monomers to dimerize when held in close proximity, we postulated that cargo binding normally regulates dimerization of myosin VI. We tested this hypothesis by expressing a known dimeric cargo adaptor protein of myosin VI, optineurin, and the myosin VI-binding segment from a monomeric cargo adaptor protein, Dab2. In the presence of these adaptor proteins, full-length myosin VI has ATPase properties of a dimer, appears as a dimer in electron micrographs, and moves processively on actin filaments. The results support a model in which cargo binding exposes internal dimerization sequences within full-length myosin VI. Because, unexpectedly, a monomeric fragment of Dab2 triggers dimerization, it would appear that myosin VI is designed to function as a dimer in cells.

SUBMITTER: Phichith D

PROVIDER: S-EPMC2753641 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature

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Cargo binding induces dimerization of myosin VI.

Phichith Denis D Travaglia Mirko M Yang Zhaohui Z Liu Xiaoyan X Zong Alan B AB Safer Daniel D Sweeney H Lee HL

Proceedings of the National Academy of Sciences of the United States of America 20090928 41

Although myosin VI has properties that would allow it to function optimally as a dimer, full-length myosin VI exists as a monomer in isolation. Based on the ability of myosin VI monomers to dimerize when held in close proximity, we postulated that cargo binding normally regulates dimerization of myosin VI. We tested this hypothesis by expressing a known dimeric cargo adaptor protein of myosin VI, optineurin, and the myosin VI-binding segment from a monomeric cargo adaptor protein, Dab2. In the p ...[more]

PMID: 19805065

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