Conservation of the regulated structure of folded myosin 2 in species separated by at least 600 million years of independent evolution

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Neil Billington (Creator)

Stan A. Burgess (Creator)

Joseph M. Chalovich (Creator)

Peter D. Chantler (Creator)

Melanie Colegrave (Creator)

Hyun Suk Jung (Creator)

Peter J. Knight (Creator)

Hitesh Patel (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: The myosin 2 family of molecular motors includes isoforms regulated n different ways. Vertebrate smooth-muscle myosin is activated by phosphorylation of the regulatory light chain whereas scallop striated adductor-muscle myosin is activated by direct calcium binding to its essential light chain. The paired heads of inhibited molecules from myosins regulated by phosphorylation have an asymmetric arrangement with motor–motor interactions. It was unknown whether such interactions were a common motif for inactivation used in other forms of myosin-linked regulation. Using electron microscopy and single-particle image processing we show that indistinguishable structures are indeed found in myosins and heavy meromyosins isolated from scallop striated adductor muscle and turkey gizzard smooth muscle. The similarities extend beyond the shapes of the heads and interactions between them: In both myosins the tail folds into three segments apparently at identical sites; all three segments are in close association outside the head region; and two segments are associated in the same way with one head in the asymmetric arrangement. Thus these organisms which have different regulatory mechanisms and diverged from a common ancestor >600 Myr ago have the same quaternary structure. Conservation across such a large volutionary distance suggests that this conformation is of fundamental unctional importance. Proceedings of the National Academy of Science Vol. 105 No. 16 Apr 2008

Additional Information

Publication

Other

Proceedings of the National Academy of Science. 105:16(April 2008) p. 6022-6026.

Language: English

Date: 2011

Keywords

electron microscopy, molluscan muscle, regulation, smooth muscle, Image processing

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