Gary R. Walker
Associate Professor
Molecular Biology and Microbiology Division

Dept. of Biological Sciences
Youngstown State University
Youngstown, OH 44555-3601
Phone: (330) 941-7177
E-mail: grwalker@cc.ysu.edu
Web Site: www.cc.ysu.edu/~grwalker

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Education Courses I Teach Research.  
The cell division cycle and cell mass is under strict temporal and spatial regulation that depends on the activity of a variety of specific protein kinases. The specific role of these kinases in regulating the changes in the actin cytoskeleton during cytokinesis is an area of focus to my research. Recently, I have developed an interest in the role of growth and cell division kinases have in cellular differentiation. I use two cell systems for these studies, the dimorphic fungi, Penicillium marneffei, and the mouse myogenic stem cell line, C2C12. Changes in cell division kinase 1,  mTOR (growth regulating protein kinase) and protein phosphorylation patterns during cellular differentiation are currently being studied, in order to understand the role of cell cycle/ growthregulation in cellular differentiation. In the fungi, differentiation (transdifferentiation) involves cells going from exhibiting the cellular morphology of filaments fungi to that of single celled yeast forms. This occurs upon shifting the temperature from 25˚C to 37˚C). C2C12 cells are a mouse stem cell line that can be induced to undergo differentiation, forming functional myotubes in culture. The inductive factors are cell density and changes in serum levels in culture media.

These studies are in addition to ongoing studies in the area of autoimmune myopathies, specifically rippling muscle disease associated with myasthenia gravis. We have identified autoantigens in patients diagnosted with rippling muscles associated with myasthenia gravis. Autoantibodies react with titin a large muscle specific protein associated with a variety of myopathies. Currently, we are applying genomic and proteomic analysis to further understand the role these antigenic epitopes have in the altered behavior of skeletal muscle fibers, as seen with these myopathies.

For more about the Walker Laboratory and Dr. Walker.

Collaborative studies with Dr. Carl Ansevin involving the autoimmune disease, myasthenia gravis.
 
 
 

Publications

T. Watkins, L. Zelinka, M. Kesic, C. R, Ansevin and G. R. Walker, Identification of skeletal muscle autoantigens by expression library screening using sera from autoimmune rippling muscle disease (ARMD) patients.  Journal of Cellular Biochemistry 99(1) 79-87 (2006).

Mark D. Womble and Gary R. Walker, “Teaching Biology to a Visually Impaired Student” Journal of College Science Teaching 30(6):394-396 (2001).

Walker, G.R, Thomas Watkins and Carl F. Ansevin, "Identification of Autoantibodies Associated with Rippling Muscles and Myasthenia Gravis that Recognize Skeletal Muscle Proteins: Possible Relationship of Antigens and Stretch-Activated Ion Channels" Biochem. Biophy. Res. Comm. 264(2): 430-435 (1999).

Walker, G , Shuster, B. and D. R. Burgess, Microtubule-entrained Kinase Activities Associated with  the Cortical Actin Cytoskeleton During Cytokinesis. Journal of Cell Science 110: 1373-1386 (1997)

Walker, G, D.R. Burgess and W.H. Kinsey, Fertilization Promotes Selective Association of the Abl-kinase with the Egg Cytoskeleton. European Journal of Cell Biology 70; 165-171 (1996)

Walker, G, Kane, R.E.and D. Burgess, Isolation and Characterization of a Sea Urchin Zygote Cortex Which Supports In Vitro Contraction
and Reactivation of Furrowing. J. Cell Science 107: 2239-2248 (1994)

Walker,G., Yabkowitz, R. and D.R. Burgess, Mapping the Binding Domain of a Myosin II-binding Protein. Biochemistry 30 (42): 10206-10210 (1991).

Walker, G. and L.Y.W. Bourguignon, Membrane-associated 41kDa GTP-Binding Protein  in Collagen-Induced Platelet Activation. FASEB Journal 4(11):2924-2933 (1990).

Bourguignon, L.Y.W., G.Walker, and H.S. Huang Interactions between a Lymphoma Membrane-Associated Guanosine
5'-Triphosphate-BindingProtein and The Cytoskeleton During Receptor Patching and Capping. J. Immunology 144: 2242-2252(1990).

Walker, G.R., J.D. Taylor and T.T. Tchen, Immunofluorescence Evidence for Cytoskeletal Rearrangement Accompanying Pigment Redistribution in Goldfish Xanthophores. Cell Motility and the Cytoskeleton 14:458-468 (1989).

Walker, G., W.G.L. Kerrick and L.Y.W. Bourguignon, The Role of Caldesmon in the Regulation of Receptor Capping in Mouse T-Lymphoma Cell. J.Biol.Chem. 264(1): 496-500 (1989).

Tchen, T.T., S.-J. Lo, T.J. Lynch, R.E. Palazzo, G. Peng, G.R. Walker, B.-Y. Wu, F.-X. Yu and J.D. Taylor, Regulation of the Distribution of Carotenoid Droplets in Goldfish Xanthophores and Possible Implication to Secretory Processes. Cell Motility and the Cytoskeleton 10:143-152 (1988).

Tchen, T.T., R.D. Allen, S.-C. J. Lo, T.J. Lynch, R.E. Palazzo, J. Hayden, G.R.Walker and J.D. Taylor, Role of Microtubules in the formation of Carotenoid Droplet Aggregate in Goldfish Xanthophores. Ann. N.Y. Acad. Sci. 466:887-894 (1986).

Bourguignon, L.Y.W., G. Walker, S.J. Suchard and K. Balazovich, A Lymphoma Plasma Membrane- Associated Protein with Ankyrin-Like Properties. J. Cell Biol. 102(6):2115-2124 (1986).

Bourguignon, L.Y.W., G. Walker and G.J. Bourguignon, Phorbol Ester-Induced Phosphorylation of a Transmembrane Glycoprotein
(GP180) in Human Blood Platelets. J. Biol. Chem. 260:11775-11780 (1985).

Walker, G.R., J. Matsumoto, J.D. Taylor and T.T. Tchen, Intermediate Filaments with Novel Protein Composition from Certain Goldfish
Cells. Biochem. Biophys. Res. Comm. 133(3):873-877 (1985).

Clark, C.R., G.R. Walker, T.J. Lynch, J.D. Taylor and T.T. Tchen, Identification of a 75d Phosphoprotein Specific to Melanophores. Pigment Cell  :37-43 (1985).