Ryoma Ohi, Ph.D.
Cell Biology Researcher
Vanderbilt University Medical Center, Department of Cell and Developmental Biology
465 21st Avenue South, 3120B MRB III
Nashville, TN 37232-8240
Microtubule organization and dynamics regulation during cell division
Our group studies animal cell division. During this process, the microtubule cytoskeleton is organized into a transient structure called the mitotic spindle. This apparatus attaches replicated chromosomes via kinetochores and generates forces that power the equal division of chromosomes among two daughter cells. We apply a multidisciplinary approach to examine the process of mitotic spindle assembly and how the interface between kinetochores and microtubules is regulated to promote error-free chromosome segregation. We use quantitative light microscopy to investigate protein behavior in the mitotic spindle, biochemistry to understand the function of key mitotic regulators, and small molecules to perturb spindle function. Currently, our lab is studying how several kinesin-like proteins impact spindle assembly and function in animal cells. We are particularly interested in the roles of the kinesin-8s at spindle microtubule plus ends, and the mechanisms by which the kinesin-5 and kinesin-12 motors enforce spindle bipolarity.
- Stumpff, J, Du, Y, English, CA, Maliga, Z, Wagenbach, M, Asbury, CL, Wordeman, L, Ohi, R A Tethering Mechanism Controls the Processivity and Kinetochore-Microtubule Plus-End Enrichment of the Kinesin-8 Kif18A. Mol Cell, 43(5), 764-75, 2011.
- Archuleta, TL, Du, Y, English, CA, Lory, S, Lesser, C, Ohi, MD, Ohi, R, Spiller, BW The Chlamydia effector, chlamydial outer protein N CopN), sequesters tubulin and prevents microtubule assembly. J Biol Chem, 2011.
- Needleman, DJ, Groen, A, Ohi, R, Maresca, T, Mirny, L, Mitchison, T Fast microtubule dynamics in meiotic spindles measured by single molecule imaging: evidence that the spindle environment does not stabilize microtubules. Mol Biol Cell, 21(2), 323-33, 2010.
- Ohi, R Kip3-ing kinetochores clustered. Cell Cycle, 9(13), 2497, 2010.
- Du, Y, English, CA, Ohi, R The kinesin-8 Kif18A dampens microtubule plus-end dynamics. Curr Biol, 20(4), 374-80, 2010.
- Maresca, TJ, Groen, AC, Gatlin, JC, Ohi, R, Mitchison, TJ, Salmon, ED Spindle Assembly in the Absence of a RanGTP Gradient Requires Localized CPC Activity. Curr Biol, 2009.
- Efimov, A, Schiefermeier, N, Grigoriev, I, Ohi, R, Brown, MC, Turner, CE, Small, JV, Kaverina, I Paxillin-dependent stimulation of microtubule catastrophes at focal adhesion sites. J Cell Sci, 121(Pt 2), 196-204, 2008.
- Germane, KL, Ohi, R, Goldberg, MB, Spiller, BW Structural and functional studies indicate that Shigella VirA is not a protease and does not directly destabilize microtubules. Biochemistry, 47(39), 10241-3, 2008.
- Coughlin, M, Brieher, WM, Ohi, R Cell-free extract systems and the cytoskeleton: preparation of biochemical experiments for transmission electron microscopy. Methods Mol Biol, 369199-212, 2007.
- Ohi, R, Burbank, K, Liu, Q, Mitchison, TJ Nonredundant Functions of Kinesin-13s during Meiotic Spindle Assembly. Curr Biol, 17(11), 953-9, 2007.
- Mitchison, TJ, Maddox, P, Groen, A, Cameron, L, Perlman, Z, Ohi, R, Desai, A, Salmon, ED, Kapoor, TM Bipolarization and poleward flux correlate during Xenopus extract spindle assembly. Mol Biol Cell, 15(12), 5603-15, 2004.
- Ohi, R, Sapra, T, Howard, J, Mitchison, TJ Differentiation of cytoplasmic and meiotic spindle assembly MCAK functions by Aurora B-dependent phosphorylation. Mol Biol Cell, 15(6), 2895-906, 2004.
- Sampath, SC, Ohi, R, Leismann, O, Salic, A, Pozniakovski, A, Funabiki, H The chromosomal passenger complex is required for chromatin-induced microtubule stabilization and spindle assembly. Cell, 118(2), 187-202, 2004.
- Groen, AC, Cameron, LA, Coughlin, M, Miyamoto, DT, Mitchison, TJ, Ohi, R XRHAMM functions in ran-dependent microtubule nucleation and pole formation during anastral spindle assembly. Curr Biol, 14(20), 1801-11, 2004.
- Ohi, R, Coughlin, ML, Lane, WS, Mitchison, TJ An inner centromere protein that stimulates the microtubule depolymerizing activity of a KinI kinesin. Dev Cell, 5(2), 309-21, 2003.
- Burns, CG, Ohi, R, Mehta, S, O'Toole, ET, Winey, M, Clark, TA, Sugnet, CW, Ares, M, Gould, KL Removal of a single alpha-tubulin gene intron suppresses cell cycle arrest phenotypes of splicing factor mutations in Saccharomyces cerevisiae. Mol Cell Biol, 22(3), 801-15, 2002.
- Burns, CG, Ohi, R, Krainer, AR, Gould, KL Evidence that Myb-related CDC5 proteins are required for pre-mRNA splicing. Proc Natl Acad Sci U S A, 96(24), 13789-94, 1999.
- Feoktistova, A, McCollum, D, Ohi, R, Gould, KL Identification and characterization of Schizosaccharomyces pombe asp1(+), a gene that interacts with mutations in the Arp2/3 complex and actin. Genetics, 152(3), 895-908, 1999.
- McDonald, WH, Ohi, R, Smelkova, N, Frendewey, D, Gould, KL Myb-related fission yeast cdc5p is a component of a 40S snRNP-containing complex and is essential for pre-mRNA splicing. Mol Cell Biol, 19(8), 5352-62, 1999.
- Ohi, R, Gould, KL Regulating the onset of mitosis. Curr Opin Cell Biol, 11(2), 267-73, 1999.
- Ohi, R, Feoktistova, A, McCann, S, Valentine, V, Look, AT, Lipsick, JS, Gould, KL Myb-related Schizosaccharomyces pombe cdc5p is structurally and functionally conserved in eukaryotes. Mol Cell Biol, 18(7), 4097-108, 1998.
- Ohi, R, Feoktistova, A, Gould, KL Construction of vectors and a genomic library for use with his3-deficient strains of Schizosaccharomyces pombe. Gene, 174(2), 315-8, 1996.
- Ohi, R, McCollum, D, Hirani, B, Den Haese, GJ, Zhang, X, Burke, JD, Turner, K, Gould, KL The Schizosaccharomyces pombe cdc5+ gene encodes an essential protein with homology to c-Myb. EMBO J, 13(2), 471-83, 1994.
- B.S., Vanderbilt University
- Ph.D., Vanderbilt University
- Postdoctoral Fellowship, Harvard Medical School