Publication Date:
2014-07-26
Description:
Proteins that cap the ends of the actin filament are essential regulators of cytoskeleton dynamics. Whereas several proteins cap the rapidly growing barbed end, tropomodulin (Tmod) is the only protein known to cap the slowly growing pointed end. The lack of structural information severely limits our understanding of Tmod's capping mechanism. We describe crystal structures of actin complexes with the unstructured amino-terminal and the leucine-rich repeat carboxy-terminal domains of Tmod. The structures and biochemical analysis of structure-inspired mutants showed that one Tmod molecule interacts with three actin subunits at the pointed end, while also contacting two tropomyosin molecules on each side of the filament. We found that Tmod achieves high-affinity binding through several discrete low-affinity interactions, which suggests a mechanism for controlled subunit exchange at the pointed end.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4367809/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4367809/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rao, Jampani Nageswara -- Madasu, Yadaiah -- Dominguez, Roberto -- GM-0080/GM/NIGMS NIH HHS/ -- R01 GM073791/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2014 Jul 25;345(6195):463-7. doi: 10.1126/science.1256159.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA. ; Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA. droberto@mail.med.upenn.edu.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25061212" target="_blank"〉PubMed〈/a〉
Keywords:
Actin Cytoskeleton/*chemistry
;
Actins/*chemistry
;
Amino Acid Sequence
;
Animals
;
Crystallography, X-Ray
;
Humans
;
Molecular Sequence Data
;
Mutation
;
Protein Binding
;
Protein Structure, Secondary
;
Protein Structure, Tertiary
;
Rabbits
;
Tropomodulin/*chemistry/genetics
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
