GERALD M. CARLSON
PROFESSOR

EDUCATION:
B.S. in Biochemistry, 1969, Washington State University
Ph.D. in Biochemistry, 1975, Iowa State University
N.I.H. Postdoctoral Fellow, 1975-1978, Institute for Enzyme Research at University of Wisconsin

RESEARCH INTERESTS: Our research group seeks to understand the physiological production of glucose through synthesis from pyruvate (gluconeogenesis) and through degradation of glycogen (glycogenolysis) by focusing upon the structure, chemistry and regulation of a key enzyme in each metabolic process.

1. Phosphorylase Kinase: This complex, oligomeric (16 subunits), highly regulated enzyme of glycogenolysis is subject to hormonal activation through phosphorylation, to neural activation by Ca2+ ions, and to metabolic activation by ADP. Little is known, however, about the physical basis underlying the activity or regulation of this key enzyme of energy production in muscle. We are studying the functions, interactions, and arrangement of the enzyme's individual subunits, the mechanisms through which Ca2+ ions activate the enzyme, the sites and consequences of various types of phosphorylation, and the interaction of the enzyme with purine nucleotides at its catalytic site and at an allosteric activating site.

2. Phosphoenolpyruvate Carboxykinase: This enzyme, which catalyzes the first committed step in the synthesis of glucose from pyruvate, is increased in response to various hormonal and dietary stimuli and is elevated as much as sixfold in diabetes. Yet, despite its key position in a central metabolic pathway, remarkably little is known about the overall structure of the enzyme or the structure of its active site. We are mapping the active site of carboxykinase through affinity labeling and other types of chemical modification to determine the location of its GTP substrate binding site, the site at which free divalent cations bind and activate, and the role of an extraordinarily reactive cysteine residue (Cys-288) that is essential for activity.

CURRENT RESEARCH SUPPORT:
NIH R01 DK 32953 "Subunit Interactions of Phosphorylase Kinase" April 1994 - March 1999; $797,487 TDC.

GRADUATE STUDENTS: (Ph.D. only)
Marita M. King, 1981; Thomas J. Fitzgerald, 1985; Alexander Cheng, 1986; Cristina Lewis, 1989; Veronica Sanchez, 1993; Deborah Wilkinson, 1993; Yi-Hong Xu, 1994; Rose Stiffin, 1995; Nancy Ayers (current student).

PUBLICATIONS: (since 1990)
Paudel, H.K. and Carlson, G.M. (1990) The quaternary structure of phosphorylase kinase as influenced by low concentrations of urea: Evidence for a structural role for calmodulin. Biochem. J., 268, 393-399.
Paudel, H.K. and Carlson, G.M. (1990) Functional and structural similarities between the inhibitory region of troponin I coded by exon VII and the calmodulin-binding regulatory region of the catalytic subunit of phosphorylase kinase. Proc. Natl. Acad. Sci. USA, 87, 7285-7289.
Paudel, H.K. and Carlson, G.M. (1991) The ATPase activity of phosphorylase kinase is regulated in parallel with its protein kinase activity. J. Biol. Chem., 266, 16524-16529.
Farrar, Y.J.K. and Carlson, G.M. (1991) Kinetic characterization of the calmodulin-activated catalytic subunit of phosphorylase kinase. Biochemistry, 30, 10274-10279.
Lewis, C.T., Seyer, J.M., and Carlson, G.M. (1992) Photochemical cross-linking of guanosine 5'-triphosphate to phosphoenolpyruvate carboxykinase (GTP). Bioconjugate Chemistry, 3, 160-166.
Lewis, C.T., Seyer, J.M., Cassell, R.G., and Carlson, G.M. (1993) Identification of vicinal thiols of phosphoenolpyruvate carboxykinase (GTP). J. Biol. Chem., 268, 1628-1636.
Farrar, Y.J.K., Lukas, T.J., Craig, T.A., Watterson, D.M., and Carlson, G.M. (1993) Features of calmodulin that are important in the activation of the catalytic subunit of phosphorylase kinase. J. Biol. Chem., 268, 4120-4125.
Sanchez, V.E. and Carlson, G.M. (1993) Isolation of an autoinhibitory region from the regulatory b-subunit of phosphorylase kinase. J. Biol. Chem., 268, 17889-17895.
Paudel, H.K., Xu, Y.-H., Jarrett, H.W., and Carlson, G.M. (1993) The model calmodulin-binding peptide melittin inhibits phosphorylase kinase by interacting with its catalytic center. Biochemistry, 32, 11865-11872.
Bender, P.K., Wang, Z., and Carlson, G.M. (1993) Two exons encode the calmodulin binding domain in the mouse phosphorylase kinase catalytic subunit gene. Genetic Analysis, 10, 99-101.
Wilkinson, D.A., Marion, T.N., Tillman, D.M., Norcum, M.T., Hainfeld, J.F., Seyer, J.M., and Carlson, G.M. (1994) An epitope proximal to the carboxyl terminus of the a-subunit is located near the lobe tips of the phosphorylase kinase hexadecamer. J. Mol. Biol., 235, 974-982.
Wilkinson, D.A., Tonin, P. Shanske, S., Lombes, A., Carlson, G.M., and DiMauro, S. (1994) Clinical and biochemical features of ten adult patients with muscle phosphorylase kinase deficiency. Neurology, 44, 461-466.
Huang, S., Carlson, G.M., and Cheung, W.Y. (1994) Calmodulin-dependent enzymes undergo a proton-induced conformational change that is associated with their interactions with calmodulin. J. Biol. Chem., 269, 7631-7638.
Norcum, M.T., Wilkinson, D.A., Carlson, M.C., Hainfeld, J.F., and Carlson, G.M. (1994) Structure of phosphorylase kinase: A three-dimensional model derived from stained and unstained electron micrographs. J. Mol. Biol., 241, 94-102.
Nadeau, O.W. and Carlson, G.M. (1994) Zero-length conformation-dependent cross-linking of phosphorylase kinase subunits by transglutaminase. J. Biol. Chem., 269, 29670-29676.