Functional redundancy and formin-independent localization of tropomyosin isoforms in Saccharomyces cerevisiae .
Autor: | Dhar A; Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka 560012, India.; equal contribution., Bagyashree VT; Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka 560012, India.; equal contribution., Biswas S; Departments of Physics, Cell Biology and Biochemistry, Emory University, Atlanta, GA, 30322, USA., Kumari J; Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka 560012, India., Sridhara A; Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka 560012, India., Jeevan Subodh B; Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka 560012, India., Shekhar S; Departments of Physics, Cell Biology and Biochemistry, Emory University, Atlanta, GA, 30322, USA., Palani S; Department of Biochemistry, Indian Institute of Science, Bengaluru, Karnataka 560012, India. |
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Jazyk: | angličtina |
Zdroj: | BioRxiv : the preprint server for biology [bioRxiv] 2024 Apr 04. Date of Electronic Publication: 2024 Apr 04. |
DOI: | 10.1101/2024.04.04.587703 |
Abstrakt: | Tropomyosin is an actin binding protein which protects actin filaments from cofilin-mediated disassembly. Distinct tropomyosin isoforms have long been hypothesized to differentially sort to subcellular actin networks and impart distinct functionalities. Nevertheless, a mechanistic understanding of the interplay between Tpm isoforms and their functional contributions to actin dynamics has been lacking. In this study, we present acetylation-mimic engineered mNeonGreen-Tpm fusion proteins that exhibit complete functionality as a sole copy, surpassing limitations of existing probes and enabling real-time dynamic tracking of Tpm-actin filaments in vivo . Using these functional Tpm fusion proteins, we find that both Tpm1 and Tpm2 indiscriminately bind to actin filaments nucleated by either formin isoform- Bnr1 and Bni1 in vivo , in contrast to the long-held paradigm of Tpm-formin pairing. We also show that Tpm2 can protect and organize functional actin cables in absence of Tpm1. Overall, our work supports a concentration-dependent and formin-independent model of Tpm-actin binding and demonstrates for the first time, the functional redundancy of the paralog Tpm2 in actin cable maintenance in S. cerevisiae . Competing Interests: Competing interest statement The authors declare no conflict of interest. |
Databáze: | MEDLINE |
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