Temperature sensitive point mutations in fission yeast tropomyosin have long range effects on the stability and function of the actin- tropomyosin copolymer

Johnson, C. A. and Brooker, H. R. and Gyamfi, I. and O’Brien, J. A. and Ashley, B. and Brazier, J. E. and Dean, A. and Embling, J. and Grimsey, E. and Tomlinson, A. C. and Wilson, E. G. and Geeves, Michael A. and Mulvihill, Daniel P. (2017) Temperature sensitive point mutations in fission yeast tropomyosin have long range effects on the stability and function of the actin- tropomyosin copolymer. Biochemical and Biophysical Research Communications, . ISSN 0006-291X. (In press) (doi:https://doi.org/10.1016/j.bbrc.2017.10.109) (Access to this publication is currently restricted. You may be able to access a copy if URLs are provided)

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Abstract

The actin cytoskeleton is modulated by regulatory actin-binding proteins which fine- tune the dynamic properties of the actin polymer to regulate function. One such actin-binding protein is tropomyosin (Tpm), a highly-conserved alpha-helical dimer which stabilises actin and regulates interactions with other proteins. Temperature sensitive mutants of Tpm are invaluable tools in the study of actin filament dependent processes, critical to the viability of a cell. Here we investigated the molecular basis of the temperature sensitivity of fission yeast Tpm mutants which fail to undergo cytokinesis at the restrictive temperatures. Comparison of Contractile Actomyosin Ring (CAR) constriction as well as cell shape and size revealed the cdc8.110 or cdc8.27 mutant alleles displayed significant differences in their temperature sensitivity and impact upon actin dependent functions during the cell cycle. In vitro analysis revealed the mutant proteins displayed a different reduction in thermostability, and unexpectedly yield two discrete unfolding domains when acetylated on their amino-termini. Our findings demonstrate how subtle changes in structure (point mutations or acetylation) alter the stability not simply of discrete regions of this conserved cytoskeletal protein but of the whole molecule. This differentially impacts the stability and cellular organisation of this essential cytoskeletal protein.

Item Type: Article
Projects: [UNSPECIFIED] BB/K012045/1
[UNSPECIFIED] BB/M015130/1
Uncontrolled keywords: Acetylation, Schizosaccharomyces pombe, fission yeast, actin cytoskeleton, Cdc8, thermal stability
Subjects: Q Science > QH Natural history > QH301 Biology
Q Science > QH Natural history > QH581.2 Cell Biology
Q Science > QR Microbiology
Divisions: Faculties > Sciences > School of Biosciences
Depositing User: Dan Mulvihill
Date Deposited: 21 Oct 2017 17:52 UTC
Last Modified: 21 Nov 2017 14:38 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/64101 (The current URI for this page, for reference purposes)
Brooker, H. R.: https://orcid.org/0000-0001-5861-4759
Geeves, Michael A.: https://orcid.org/0000-0002-9364-8898
Mulvihill, Daniel P.: https://orcid.org/0000-0003-2502-5274
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