A small molecule inhibitor of tropomyosin dissociates actin binding from tropomyosin-directed regulation of actin dynamics

Teresa T. Bonello, Miro Janco, Jeff Hook, Alex Byun, Mark Appaduray, Irina Dedova, Sarah Hitchcock-DeGregori, Edna C. Hardeman, Justine R. Stehn, Till Böcking, Peter W. Gunning*

*Corresponding author for this work

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18 Citations (Scopus)
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Abstract

The tropomyosin family of proteins form end-to-end polymers along the actin filament. Tumour cells rely on specific tropomyosin-containing actin filament populations for growth and survival. To dissect out the role of tropomyosin in actin filament regulation we use the small molecule TR100 directed against the C terminus of the tropomyosin isoform Tpm3.1. TR100 nullifies the effect of Tpm3.1 on actin depolymerisation but surprisingly Tpm3.1 retains the capacity to bind F-actin in a cooperative manner. In vivo analysis also confirms that, in the presence of TR100, fluorescently tagged Tpm3.1 recovers normally into stress fibers. Assembling end-to-end along the actin filament is thereby not sufficient for tropomyosin to fulfil its function. Rather, regulation of F-actin stability by tropomyosin requires fidelity of information communicated at the barbed end of the actin filament. This distinction has significant implications for perturbing tropomyosin-dependent actin filament function in the context of anti-cancer drug development.

Original languageEnglish
Article number19816
Number of pages7
JournalScientific Reports
Volume6
DOIs
Publication statusPublished - 25 Jan 2016
Externally publishedYes

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