TY - JOUR
T1 - Docking and stability defects in mitofusin highlight the proteasome as a potential therapeutic target
AU - Buntenbroich, Ira
AU - Anton, Vincent
AU - Perez-Hernandez, Daniel
AU - Simões, Tânia
AU - Gaedke, Felix
AU - Schauss, Astrid
AU - Dittmar, Gunnar
AU - Riemer, Jan
AU - Escobar-Henriques, Mafalda
N1 - Funding Information:
We would like to thank T Sommer for the Cdc48 and Ubc6 antibodies and ML Mendes for help with the analysis of mass spectrometry after cross-linking. This work was supported by grants from Deutsche Forschungsgemeinschaft (DFG, German Research Foundation ) ( CRC 1218 TP A03 ; EXC 2030–390661388 ; to M.E-H.), from the Center for Molecular Medicine Cologne (CMMC; CAP14 to M.E-H. and A02 to M.E-H. and M.O.), from the Boehringer Ingelheim Foundation (BIS; Exploration grant, to M.E-H.) and was funded under the Institutional Strategy of the University of Cologne within the German Excellence Initiative ( ZUK 81/1 , to M.E-H.).
Funding Information:
We would like to thank T Sommer for the Cdc48 and Ubc6 antibodies and ML Mendes for help with the analysis of mass spectrometry after cross-linking. This work was supported by grants from Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) (CRC 1218 TP A03; EXC 2030–390661388; to M.E-H.), from the Center for Molecular Medicine Cologne (CMMC; CAP14 to M.E-H. and A02 to M.E-H. and M.O.), from the Boehringer Ingelheim Foundation (BIS; Exploration grant, to M.E-H.) and was funded under the Institutional Strategy of the University of Cologne within the German Excellence Initiative (ZUK 81/1, to M.E-H.). I.B. V.A. and M.E-H. designed the study and wrote the manuscript, with input from all authors. I.B. and V.A. performed most experiments and prepared the figures. D.P-H. performed the mass spectrometry analysis under the supervision of G.D. T.S performed the Fzo1-Cdc48 co-immunoprecipitations. F.G performed transmission electron microscopy experiments, under the supervision of A.S. J.R read the manuscript and provided input on the design of the study. M.E-H. coordinated the study. The authors declare no competing interests.
Publisher Copyright:
© 2023 The Author(s)
PY - 2023/7/21
Y1 - 2023/7/21
N2 - Defects in mitochondrial fusion are at the base of many diseases. Mitofusins power membrane-remodeling events via self-interaction and GTP hydrolysis. However, how exactly mitofusins mediate fusion of the outer membrane is still unclear. Structural studies enable tailored design of mitofusin variants, providing valuable tools to dissect this stepwise process. Here, we found that the two cysteines conserved between yeast and mammals are required for mitochondrial fusion, revealing two novel steps of the fusion cycle. C381 is dominantly required for the formation of the trans-tethering complex, before GTP hydrolysis. C805 allows stabilizing the Fzo1 protein and the trans-tethering complex, just prior to membrane fusion. Moreover, proteasomal inhibition rescued Fzo1 C805S levels and membrane fusion, suggesting a possible application for clinically approved drugs. Together, our study provides insights into how assembly or stability defects in mitofusins might cause mitofusin-associated diseases and uncovers potential therapeutic intervention by proteasomal inhibition.
AB - Defects in mitochondrial fusion are at the base of many diseases. Mitofusins power membrane-remodeling events via self-interaction and GTP hydrolysis. However, how exactly mitofusins mediate fusion of the outer membrane is still unclear. Structural studies enable tailored design of mitofusin variants, providing valuable tools to dissect this stepwise process. Here, we found that the two cysteines conserved between yeast and mammals are required for mitochondrial fusion, revealing two novel steps of the fusion cycle. C381 is dominantly required for the formation of the trans-tethering complex, before GTP hydrolysis. C805 allows stabilizing the Fzo1 protein and the trans-tethering complex, just prior to membrane fusion. Moreover, proteasomal inhibition rescued Fzo1 C805S levels and membrane fusion, suggesting a possible application for clinically approved drugs. Together, our study provides insights into how assembly or stability defects in mitofusins might cause mitofusin-associated diseases and uncovers potential therapeutic intervention by proteasomal inhibition.
KW - Biological sciences
KW - Cell biology
KW - Genetics
KW - Molecular biology
UR - http://www.scopus.com/inward/record.url?scp=85162248548&partnerID=8YFLogxK
UR - https://pubmed.ncbi.nlm.nih.gov/37416455
U2 - 10.1016/j.isci.2023.107014
DO - 10.1016/j.isci.2023.107014
M3 - Article
C2 - 37416455
AN - SCOPUS:85162248548
SN - 2589-0042
VL - 26
JO - iScience
JF - iScience
IS - 7
M1 - 107014
ER -