Christopher S. Cohan PhD
Christopher S. Cohan
PhD
SUNY Distinguished Teaching Professor
Department of Pathology and Anatomical Sciences
Jacobs School of Medicine & Biomedical Sciences
Specialty/Research Focus
Anatomic Pathology
Professional Summary:
Previous experiments have focused on the dynamics of microtubule assembly in spindles during the process of meiosis using live imaging of fluorescent labeled microtubules. We utilized cranefly spermatocytes isolated into acute cultures containing cells at various stages of cell division that can be studied for several hours. Microtubule dynamics are studied by the technique of fluorescent speckle imaging whereby spermatocytes are injected with low concentrations of fluorescent-labeled tubulin that incorporates into microtubules at low density. This creates a patterned, discontinuous labeling of microtubules that enables quantification of the rates and sites of assembly. Our experiments examined the role of tension as a modulator of microtubule polymerization during anaphase of cell division. Chromosome kinetochores exert dragging forces on attached microtubule ends favoring microtubule assembly as chromosomes move from spindle equator to spindle poles. However, microtubule disassembly is induced when dragging forces are eliminated by laser ablation of attached chromosomes. These observations reveal some of the self-organizing mechanisms that control the orderly separation of chromosomes during cell division.
In easrlier experiments, we studied cytoskeletal changes in neuronal growth cones as they navigated through their environment. Reorganization of actin filaments and microtubules was visualized using fluorescent cytoskeletal analogs in neuronal cultures. Dynamic flow of actin filaments in growth cone lamellipodia and their effect on microtubule extension into growth cones was studied to understand the basis of growth cone turning.
Current work is devoted to creating specimens for the Brain Museum in the Jacobs School and maintaining its collection. This is a resource for our medical students learning about the brain and for visitors to the school. It provides a unique opportunity to see a human brain.
As part of my commitment to teaching, I also am course director for the Neuroscience and Behavior module for second year medical students. I have developed numerous teaching materials, including a dedicated web site. I have recently made major organizational changes to the teaching format of the module to emphasize self-directed learning and problem-solving
Education and Training:
- Certificate, Educational Informatics, University at Buffalo (2008)
- Anatomy, Case Western Reserve University (1980)
- BS, Biology/Mathematics, University at Albany, SUNY (1974)
Employment:
- Chair, Phase 1 Committee for Preclinical Medicine, Jacobs School (2018-present)
- Chair, Research Promotions Committee, Jacobs School (2018-present)
- SUNY Distinguished Teaching Professor, Pathology and Anatomical Sciences, SUNY (2018-present)
- Professor, Pathology and Anatomical Sciences, University at Buffalo (2005–2018)
- Chair, Jacobs School Curriculum Committee, Jacobs School (2009–2012)
- Associate Professor, Anatomy and Cell Biology, University at Buffalo (1992–2005)
- Assistant Professor, Anatomy and Cell Biology, University at Buffalo (1986–1992)
- Post Doctoral Fellow, Biological Sciences, University of Iowa (1980–1986)
Awards and Honors:
- Siegel Teaching Award (2016)
- Siegel Teaching Award (2012)
- Siegel Teaching Award (2009)
- Siegel Teaching Award (2007)
- SUNY Chancellor‘s Award for Excellence in Teaching (2005)
- Induction into Alpha Omega Alpha (AOA) (2005)
- Siegel Teaching Award (2004)
- Siegel Teaching Award (2003)
Research Expertise:
- Cytoskeletal Dynamics
Journal Articles:
- Yu, C, Tan, YH, Choi, M, Stanenas, AJ, Byrd, AK, Raney, K, Bianco, P and Cohan, CS. (2016) SSB binds to the RecG and PriA helicases in vivo in the absence of DNA. Genes To Cells (Dec), 21: 163-184.
- LaFountain JR, Cohan CS, Oldenbourg R. (2012) Pac-man motility of kinetochores unleashed by laser microsurgery. Mol Biol Cell (Aug), 23(16)
- Lafountain Jr., J.R., Cohan CS, Oldenbourg, R. (2012) Pac-man motility of kinetochores unleashed by laser microsurgery. Molec Biol Cell (Jan), 23
- Bianco PR, Stanenas AJ, Liu J, Cohan CS, Bianco P. (2012) Fluorescent single-stranded DNA-binding proteins enable in vitro and in vivo studies. Methods Mol Biol (Jan), 922
- LaFountain JR, Cohan CS, Oldenbourg R. (2011) Functional states of kinetochores revealed by laser microsurgery and fluorescent speckle microscopy. Mol Biol Cell (Dec), 22(24)
- Lafountain Jr, J.R., Cohan CS, Oldenbourg, R. (2011) Functional states of kinetochores revealed by laser microsurgery and fluorescent speckle microscopy. Molec Biol Cell (Jan), 22
- Torreano PJ, Waterman-Storer CM, Cohan CS. (2005) The effects of collapsing factors on F-actin content and microtubule distribution of Helisoma growth cones. Cell Motil Cytoskeleton (Mar), 60(3)
- LaFountain JR, Cohan CS, Siegel AJ, LaFountain DJ. (2004) Direct visualization of microtubule flux during metaphase and anaphase in crane-fly spermatocytes. Mol Biol Cell (Dec), 15(12)
- Zhou FQ, Cohan CS. (2004) How actin filaments and microtubules steer growth cones to their targets. J Neurobiol (Jan), 58(1)
- Torreano PJ, Cohan CS. (2003) Calcium and voltage dependent inactivation of sodium and calcium currents limits calcium influx in Helisoma neurons. J Neurobiol (Feb), 54(3)
- Adams MC, Salmon WC, Gupton SL, Cohan CS, Wittmann T, Prigozhina N, Waterman-Storer CM. (2003) A high-speed multispectral spinning-disk confocal microscope system for fluorescent speckle microscopy of living cells. Methods (Jan), 29(1)
- Zhou FQ, Waterman-Storer CM, Cohan CS. (2002) Focal loss of actin bundles causes microtubule redistribution and growth cone turning. J Cell Biol (May), 157(5)
- Zhou FQ, Cohan CS. (2001) Growth cone collapse through coincident loss of actin bundles and leading edge actin without actin depolymerization. J Cell Biol (May), 153(5)
- Cohan CS, Welnhofer EA, Zhao L, Matsumura F, Yamashiro S. (2001) Role of the actin bundling protein fascin in growth cone morphogenesis: localization in filopodia and lamellipodia. Cell Motil Cytoskeleton (Feb), 48(2)
- Hashino E, Johnson EM, Milbrandt J, Shero M, Salvi RJ, Cohan CS. (1999) Multiple actions of neurturin correlate with spatiotemporal patterns of Ret expression in developing chick cranial ganglion neurons. J Neurosci (Oct), 19(19)
- Herring TL, Cohan CS, Welnhofer EA, Mills LR, Morris CE. (1999) F-actin at newly invaginated membrane in neurons: implications for surface area regulation. J Membr Biol (Sep), 171(2)
- Welnhofer EA, Zhao L, Cohan CS. (1999) Calcium influx alters actin bundle dynamics and retrograde flow in Helisoma growth cones. J Neurosci (Sep), 19(18)
- Torreano PJ, Cohan CS. (1997) Electrically induced changes in Ca2+ in Helisoma neurons: regional and neuron-specific differences and implications for neurite outgrowth. J Neurobiol (Feb), 32(2)
- Zou JY, Cohan C, Rabin RA, Pentney RJ. (1995) Continuous exposure of cultured rat cerebellar macroneurons to ethanol-depressed NMDA and KCl-stimulated elevations of intracellular calcium. Alcohol Clin Exp Res (Aug), 19(4)
- Williams DK, Cohan CS. (1995) Calcium transients in growth cones and axons of cultured Helisoma neurons in response to conditioning factors. J Neurobiol (May), 27(1)
- Williams DK, Cohan CS. (1994) The role of conditioning factors in the formation of growth cones and neurites from the axon stump after axotomy. Brain Res Dev Brain Res (Aug), 81(1)
- Bianchi LM, Cohan CS. (1991) Developmental regulation of a neurite-promoting factor influencing statoacoustic neurons. Brain Res Dev Brain Res (Dec), 64(1-2)
- Polak KA, Edelman AM, Wasley JW, Cohan CS. (1991) A novel calmodulin antagonist, CGS 9343B, modulates calcium-dependent changes in neurite outgrowth and growth cone movements. J Neurosci (Feb), 11(2)
- Cohan CS, Errick JE, Xia MH. (1990) Formation of electrical connections between cultured identified neurons and muscle fibers of the snail Helisoma. Brain Res Dev Brain Res (Oct), 56(1)
- Cohan CS, Connor JA, Kater SB. (1987) Electrically and chemically mediated increases in intracellular calcium in neuronal growth cones. J Neurosci (Nov), 7(11)
Books and Book Chapters:
- Lafountain Jr. and Cohan, C.S. (2018) Methods to study meiosis in insect spermatocytes. In: Model Systems for Studying Cell Division. Methods in Cell Biology
Service Activities:
- Provide tours of Brain museum throughout the year for individuals and schools within and outside the Buffalo area.; Museum Curator (2021)
- Support faculty mentorship, development, and promotion.; Vice Chair Faculty Affairs (2021–present)
- Faculty leader training residents and Jacobs School faculty in learning effectiveness.; Jacobs Educator Excellence Program (2019–present)
- Core Curriculum design team for major curricular revision beginning 2023; Member (2019–2023)
- Research Promotions Committee; Chair (2019–present)
- Phase I Preclinical Curriculum Sub Committee; Chair (2018–present)
- Committee on Appointments and Promotions; Chair (2016–present)
- Curriculum Committee; Member (2012–present)
- Alpha Omega Alpha Honor Medical Society; Secretary/Treasurer (2012–present)
- Curriculum Committee; Chair (2009–2012)
- Maintain Brain Museum collections in the Jacobs School and on the south campus; Museum Curator (2008–present)
- Curator, Museum of Neuroanatomy; Director (2008–present)
- NIH and NSF Grant Review; Study Section Member (1989–2005)
- Journals included: Brain Research Bulletin Journal of Neurobiology Journal of Neuroscience Developmental Neurobiology Developmental Biology Cell and Tissue Research Invertebrate Neuroscience Growth, Development, and Aging. Molecular and Cellular Neuroscience; Manuscript review (1987–present)