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Ishida H, Woodman AG, Kitada N, Aizawa T, Vogel HJ. The Dictyostelium discoideum FimA protein, unlike yeast and plant fimbrins, is regulated by calcium similar to mammalian plastins. Sci Rep 2023; 13:16208. [PMID: 37758724 PMCID: PMC10533516 DOI: 10.1038/s41598-023-42682-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
Plastins, also known as fimbrins, are highly conserved eukaryotic multidomain proteins that are involved in actin-bundling. They all contain four independently folded Calponin Homology-domains and an N-terminal headpiece that is comprised of two calcium-binding EF-hand motifs. Since calcium-binding has been shown to be integral to regulating the activity of the three mammalian plastin proteins, we decided to study the properties of the headpiece regions of fimbrins from the model plant Arabidopsis thaliana, the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe and the amoeba Dictyostelium discoideum. Of these protein domains only the FimA headpiece from the amoeba protein possesses calcium binding properties. Structural characterization of this protein domain by multidimensional NMR and site-directed mutagenesis studies indicates that this EF-hand region of FimA also contains a regulatory 'switch helix' that is essential to regulating the activity of the human L-plastin protein. Interestingly this regulatory helical region seems to be lacking in the plant and yeast proteins and in fimbrins from all other nonmotile systems. Typical calmodulin antagonists can displace the switch-helix from the FimA headpiece, suggesting that such drugs can deregulate the Ca2+-regulation of the actin-bunding in the amoeba, thereby making it a useful organism for drug screening against mammalian plastins.
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Affiliation(s)
- Hiroaki Ishida
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Andrew G Woodman
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Naoya Kitada
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Tomoyasu Aizawa
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Hans J Vogel
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, Calgary, AB, T2N 1N4, Canada.
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Kwon E, Pathak D, Kim HU, Dahal P, Ha SC, Lee SS, Jeong H, Jeoung D, Chang HW, Jung HS, Kim DY. Structural insights into stressosome assembly. IUCRJ 2019; 6:938-947. [PMID: 31576226 PMCID: PMC6760441 DOI: 10.1107/s205225251900945x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 07/02/2019] [Indexed: 05/05/2023]
Abstract
The stressosome transduces environmental stress signals to SigB to upregulate SigB-dependent transcription, which is required for bacterial viability. The stressosome core is composed of RsbS and at least one of the RsbR paralogs. A previous cryo-electron microscopy (cryo-EM) structure of the RsbRA-RsbS complex determined under a D2 symmetry restraint showed that the stressosome core forms a pseudo-icosahedron consisting of 60 STAS domains of RsbRA and RsbS. However, it is still unclear how RsbS and one of the RsbR paralogs assemble into the stressosome. Here, an assembly model of the stressosome is presented based on the crystal structure of the RsbS icosahedron and cryo-EM structures of the RsbRA-RsbS complex determined under diverse symmetry restraints (nonsymmetric C1, dihedral D2 and icosahedral I envelopes). 60 monomers of the crystal structure of RsbS fitted well into the I-restrained cryo-EM structure determined at 4.1 Å resolution, even though the STAS domains in the I envelope were averaged. This indicates that RsbS and RsbRA share a highly conserved STAS fold. 22 protrusions observed in the C1 envelope, corresponding to dimers of the RsbRA N-domain, allowed the STAS domains of RsbRA and RsbS to be distinguished in the stressosome core. Based on these, the model of the stressosome core was reconstructed. The mutation of RsbRA residues at the binding interface in the model (R189A/Q191A) significantly reduced the interaction between RsbRA and RsbS. These results suggest that nonconserved residues in the conserved STAS folds between RsbS and RsbR paralogs determine stressosome assembly.
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Affiliation(s)
- Eunju Kwon
- College of Pharmacy, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Republic of Korea
| | - Deepak Pathak
- College of Pharmacy, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Republic of Korea
| | - Han-ul Kim
- Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Pawan Dahal
- College of Pharmacy, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Republic of Korea
| | - Sung Chul Ha
- Pohang Accelerator Laboratory (PAL), Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Seung Sik Lee
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 56212, Republic of Korea
- Department of Radiation Science and Technology, University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Hyeongseop Jeong
- Center for Electron Microscopy Research, Korea Basic Science Institute, Ochang 28119, Republic of Korea
| | - Dooil Jeoung
- Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Hyeun Wook Chang
- College of Pharmacy, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Republic of Korea
| | - Hyun Suk Jung
- Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Dong Young Kim
- College of Pharmacy, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Republic of Korea
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