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Yeh MC, Hsu NH, Chu HY, Yang CH, Hsu PH, Chou CC, Shie JT, Lee WM, Ho MC, Lo KY. Dual protection by Bcp1 and Rkm1 ensures incorporation of uL14 into pre-60S ribosomal subunits. J Cell Biol 2024; 223:e202306117. [PMID: 39007857 PMCID: PMC11248248 DOI: 10.1083/jcb.202306117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 02/13/2024] [Accepted: 04/19/2024] [Indexed: 07/16/2024] Open
Abstract
Eukaryotic ribosomal proteins contain extended regions essential for translation coordination. Dedicated chaperones stabilize the associated ribosomal proteins. We identified Bcp1 as the chaperone of uL14 in Saccharomyces cerevisiae. Rkm1, the lysine methyltransferase of uL14, forms a ternary complex with Bcp1 and uL14 to protect uL14. Rkm1 is transported with uL14 by importins to the nucleus, and Bcp1 disassembles Rkm1 and importin from uL14 simultaneously in a RanGTP-independent manner. Molecular docking, guided by crosslinking mass spectrometry and validated by a low-resolution cryo-EM map, reveals the correlation between Bcp1, Rkm1, and uL14, demonstrating the protection model. In addition, the ternary complex also serves as a surveillance point, whereas incorrect uL14 is retained on Rkm1 and prevented from loading to the pre-60S ribosomal subunits. This study reveals the molecular mechanism of how uL14 is protected and quality checked by serial steps to ensure its safe delivery from the cytoplasm until its incorporation into the 60S ribosomal subunit.
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Affiliation(s)
- Min-Chi Yeh
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Ning-Hsiang Hsu
- Department of Agricultural Chemistry, College of Bioresources and Agriculture, National Taiwan University, Taipei, Taiwan
| | - Hao-Yu Chu
- Department of Agricultural Chemistry, College of Bioresources and Agriculture, National Taiwan University, Taipei, Taiwan
| | - Cheng-Han Yang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Pang-Hung Hsu
- Department of Bioscience and Biotechnology, College of Life Science, National Taiwan Ocean University, Keelung, Taiwan
- Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan
| | - Chi-Chi Chou
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Jing-Ting Shie
- Department of Agricultural Chemistry, College of Bioresources and Agriculture, National Taiwan University, Taipei, Taiwan
| | - Wei-Ming Lee
- Department of Agricultural Chemistry, College of Bioresources and Agriculture, National Taiwan University, Taipei, Taiwan
| | - Meng-Chiao Ho
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Institute of Biochemical Sciences, College of Life Science, National Taiwan University, Taipei, Taiwan
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Kai-Yin Lo
- Department of Agricultural Chemistry, College of Bioresources and Agriculture, National Taiwan University, Taipei, Taiwan
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Foltman M, Mendez I, Bech-Serra JJ, de la Torre C, Brace JL, Weiss EL, Lucas M, Queralt E, Sanchez-Diaz A. TOR complex 1 negatively regulates NDR kinase Cbk1 to control cell separation in budding yeast. PLoS Biol 2023; 21:e3002263. [PMID: 37647291 PMCID: PMC10468069 DOI: 10.1371/journal.pbio.3002263] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 07/19/2023] [Indexed: 09/01/2023] Open
Abstract
The target of rapamycin (TOR) signalling pathway plays a key role in the coordination between cellular growth and the cell cycle machinery in eukaryotes. The underlying molecular mechanisms by which TOR might regulate events after anaphase remain unknown. We show for the first time that one of the 2 TOR complexes in budding yeast, TORC1, blocks the separation of cells following cytokinesis by phosphorylation of a member of the NDR (nuclear Dbf2-related) protein-kinase family, the protein Cbk1. We observe that TORC1 alters the phosphorylation pattern of Cbk1 and we identify a residue within Cbk1 activation loop, T574, for which a phosphomimetic substitution makes Cbk1 catalytically inactive and, indeed, reproduces TORC1 control over cell separation. In addition, we identify the exocyst component Sec3 as a key substrate of Cbk1, since Sec3 activates the SNARE complex to promote membrane fusion. TORC1 activity ultimately compromises the interaction between Sec3 and a t-SNARE component. Our data indicate that TORC1 negatively regulates cell separation in budding yeast by participating in Cbk1 phosphorylation, which in turn controls the fusion of secretory vesicles transporting hydrolase at the site of division.
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Affiliation(s)
- Magdalena Foltman
- Mechanisms and Regulation of Cell Division Research Unit, Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, Santander, Spain
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
| | - Iván Mendez
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
- Structural Biology of Macromolecular Complexes Research Unit, Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, Santander, Spain
| | - Joan J. Bech-Serra
- Josep Carreras Leukaemia Research Institute, IJC Building, Campus ICO-Germans Trias i Pujol, Barcelona, Spain
| | - Carolina de la Torre
- Josep Carreras Leukaemia Research Institute, IJC Building, Campus ICO-Germans Trias i Pujol, Barcelona, Spain
| | - Jennifer L. Brace
- Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, Illinois, United States of America
| | - Eric L. Weiss
- Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, Illinois, United States of America
| | - María Lucas
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
- Structural Biology of Macromolecular Complexes Research Unit, Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, Santander, Spain
| | - Ethel Queralt
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain
| | - Alberto Sanchez-Diaz
- Mechanisms and Regulation of Cell Division Research Unit, Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, Santander, Spain
- Departamento de Biología Molecular, Facultad de Medicina, Universidad de Cantabria, Santander, Spain
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Ghosh C, Uppala JK, Sathe L, Hammond CI, Anshu A, Pokkuluri PR, Turk BE, Dey M. Phosphorylation of Pal2 by the protein kinases Kin1 and Kin2 modulates HAC1 mRNA splicing in the unfolded protein response in yeast. Sci Signal 2021; 14:14/684/eaaz4401. [PMID: 34035143 DOI: 10.1126/scisignal.aaz4401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
During cellular stress in the budding yeast Saccharomyces cerevisiae, an endoplasmic reticulum (ER)-resident dual kinase and RNase Ire1 splices an intron from HAC1 mRNA in the cytosol, thereby releasing its translational block. Hac1 protein then activates an adaptive cellular stress response called the unfolded protein response (UPR) that maintains ER homeostasis. The polarity-inducing protein kinases Kin1 and Kin2 contribute to HAC1 mRNA processing. Here, we showed that an RNA-protein complex that included the endocytic proteins Pal1 and Pal2 mediated HAC1 mRNA splicing downstream of Kin1 and Kin2. We found that Pal1 and Pal2 bound to the 3' untranslated region (3'UTR) of HAC1 mRNA, and a yeast strain lacking both Pal1 and Pal2 was deficient in HAC1 mRNA processing. We also showed that Kin1 and Kin2 directly phosphorylated Pal2, and that a nonphosphorylatable Pal2 mutant could not rescue the UPR defect in a pal1Δ pal2Δ strain. Thus, our work uncovers a Kin1/2-Pal2 signaling pathway that coordinates HAC1 mRNA processing and ER homeostasis.
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Affiliation(s)
- Chandrima Ghosh
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
| | - Jagadeesh Kumar Uppala
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
| | - Leena Sathe
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
| | - Charlotte I Hammond
- Department of Biological Sciences, Quinnipiac University, Hamden, CT 06518, USA
| | - Ashish Anshu
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA
| | - P Raj Pokkuluri
- Bioscience Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Benjamin E Turk
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Madhusudan Dey
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA.
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