Professor of Biochemistry
B.A. University of California, Berkeley
Ph.D. University of California, Los Angeles
Janet Shaw's Lab Page
Janet Shaw's PubMed Literature Search
Molecular Biology Program
Biological Chemistry Program
Mitochondrial Dynamics and Disease
The Shaw laboratory uses yeast, mammalian cells and mice to study how mitochondrial fission, fusion and movement regulate mitochondrial function and dysfunction in single cells and whole organisms. Our studies are directly relevant to human heath and disease. Defects in mitochondrial membrane dynamics cause embryonic lethality in multicellular organisms and inherited neurological disorders in humans.
In most cells, mitochondria are organized as highly branched tubular networks. This network is dynamic, undergoing frequent fission and fusion events and moving around on cytoskeletal tracks. Fission, fusion and transport are regulated by novel GTPases that are conserved from yeast to man.
Mitochondrial fission plays critical roles during development and the cell cycle and is also required for the turnover and degradation of damaged mitochondrial compartments. Our lab identified the first molecular mediator of mitochondrial fission, a dynamin-related GTPase called Dnm1. Dnm1 forms spirals on the outer mitochondrial membrane that ‘clip’ mitochondrial tubules into smaller pieces. Two additional molecules, called Fis1 and Mdv1, work together with Dnm1 during the fission reaction. We use a multidisciplinary approach to study how the multi-protein fission complex assembles, constricts and severs the mitochondrial membrane.
Mitochondrial fusion allows exchange of metabolites, proteins and mtDNA and is critical for optimal mitochondrial function. The Fzo1 GTPase is embedded in the outer mitochondrial membrane and mediates outer membrane fusion. A second GTPase, Mgm1, mediates inner membrane fusion. Mutations in the human homologs of Mgm1 and Fzo1 cause inherited neurological diseases including dominant optic atrophy and Charcot-Marie-Tooth Syndrome. We collaborate with researchers at the University of Utah and the National Institutes of Health to identify the molecular basis of these disorders in humans.
Mitochondrial movement positions these organelles in all cells and is critical in highly polarized cells such as neurons. Miro proteins are large GTPases on the mitochondrial surface, which bind molecular motors that move mitochondria along cytoskeletal tracks. Mammals have two Miro homologs, Miro1 and Miro2. We have generated Miro knockout mice and are studying the role of Miro proteins in development and neuropathy.
Mitochondrial fusion in human fibroblast cells
Unfused mitochondria are red or green. Fused mitochondria are yellow. Nuclei are blue. (B. Amiott and P. Lott)
- Nguyen, T.T., Oh S.-S., Weaver, D., Lewandowska, A., Maxfield, D., Schuler, M.-H., Smith, N.K., Macfarlane, J., Saunders, G., Palmer, C.A., Debattisti, V., Koshiba, T., Pulst, S.M., Feldman, E.L., Hajnóczky, G. and Shaw, J.M. (2014) Loss of Miro1-directed mitochondrial movement results in a novel murine model for neuron disease. Proc Natl Acad Sci U S A, 111(35), E3631-40.
- Bui, H.T. and Shaw, J.M. (2013) Dynamin assembly strategies and adaptor proteins in mitochondrial fission. Curr Biol, 23(19), R891-9.
- Lewandowska, A., Macfarlane, J., and Shaw, J.M. (2013) Mitochondrial association, protein phosphorylation and degradation regulate the availability of the active Rab GTPase, Ypt11, for mitochondrial inheritance. Mol Biol Cell, 24(8), 1185-95.
- Koirala, S., Guo, Q.*, Kalia, R.*, Bui, H.T., Eckert, D.M., Frost, A.**, and Shaw J.M.** (2013) Interchangeable adaptors regulate mitochondrial dynamin assembly for membrane scission. Proc Natl Acad Sci U S A, 110(15), E1342-51. *contributed equally; **co-communicating.
- Bui, H.T., Karren, M.A., Bhar, D., and Shaw, J.M. (2012) A novel motif in the yeast mitochondrial dynamin Dnm1 is essential for adaptor binding and membrane recruitment. J Cell Biol, 199(4), 613-22. (Subject of JCB In this issue)
- Guo, Q., Koirala, S., Perkins, E.M., McCaffery, J.M., and Shaw, J.M. (2012) The mitochondrial fission adaptors Caf4 and Mdv1 are not functionally equivalent. PLoS One, 7(12), e53523.
- Nguyen, T.T.*, Lewandowska, A.*, Choi, J.Y.*, Markgraf, D.F.*, Junker, M., Bilgin, M., Ejsing, C.S., Voelker, D.R.**, Rapoport, T.A.**, and Shaw, J.M.** (2012) Gem1 and ERMES do not directly affect phosphatidylserine transport from ER to mitochondria or mitochondrial inheritance. Traffic, 13(6), 880-890. *contributed equally; **co-communicating.
- Cohen, M.M., Amiott, E.A., Day, A.R., Leboucher, G.P., Pryce, E.N., Glickman, M.H., McCaffery, J.M., Shaw, J.M., and Weissman, A.M. (2011) Sequential requirements for the GTPase domain of the mitofusion Fzo1 and the ubiquitin ligase SCFMdm30 in mitochondrial outer membrane fusion. J Cell Sci, 124(9), 1403-1410.
- Koshiba, T.*, Holman, H., Kai, Y., Kubara, K., Kawabata, S.-I., Okamoto, K., and Shaw, J.M. (2010) Mitochondrial Inheritance mediated by the yeast Miro protein Gem1 requires activities of both GTPase domains and EF-hand motifs. J Biol Chem, 286(1), 354-362. *communicating author
- Koirala, S., Bui, H.T., Schubert, H.L., Eckert, D.M., Hill, C.P., Kay, M.S.*, and Shaw, J.M.* (2010) Molecular architecture of a dynamin adaptor: implications for assembly of mitochondrial fission complexes. J Cell Biology, 191(6), 1127-39. *co-communicating authors. (This article was the subject of JCB In Focus)
- Amiott, E.A., Cohen, M.M., Saint-Georges, Y., Weissman, A.M., and Shaw, J.M. (2009) A mutation associated with CMTA neuropathy causes defects in Fzo1 GTP hydrolysis, ubiquitylation, and protein turnover. Mol Biol Cell, 20(23), 5026-5035. (This article was featured in the "InCytes" section of American Society of Cell Biology Newsletter and nominated for paper of the year in the journal Molecular Biology of the Cell)
- Amiott, E.A., Lott, P., Soto, J., Kang, P.B., McCaffery, J.M., DiMauro, S., Abel, E.D., Flanigan, K.M., Lawson, V.*, and Shaw, J.M.* (2008) Mitochondrial fusion and function in Charcot-Marie Tooth Type 2A fibroblasts with mitofusin 2 mutations. Experimental Neurology 211(1), 115-127. *co-communicating authors.
- Kondo-Okamoto, N., Shaw, J.M.*, and Okamoto, K.* (2008) Tetratricopeptide repeat proteins Tom70 and Tom71 mediate yeast mitochondrial morphogenesis. EMBO Reports, 9(1), 63-9. *co-communicating authors.