Cynthia Czajkowski

 

 

The Structure and Function of the GABAA Receptor

E-mail: cmczajko@wisc.edu

Office Phone: (608) 265-5863, (608) 265-5864

Research Strengths: Membrane Excitability and Synaptic Transmission, Molecular Neuroscience

The major focus of the lab is on understanding the function and structure of the GABAA receptor. GABAA receptors are the major inhibitory neurotransmitter-gated-ion-channels in the brain. While GABA controls the opening of an intrinsic anion-conducting channel, GABAA receptor function is modulated by a variety of clinically important classes of drugs, including benzodiazepines, barbiturates, volatile anesthetics, neuroactive steroids and alcohol. Clinically, benzodiazepines, barbiturates and neuroactive steroids are used in the treatments of epilepsy, anxiety and panic disorders as well as other psychiatric illnesses. Recently, mutations in the GABAA receptor have been linked to human epilepsy. Using computational modeling, protein chemistry, electrophysiological and molecular biological approaches, we are mapping and identifying the amino acid residues that form the binding sites for GABA as well as for therapeutic drugs that bind to the receptor. Ultimately, a clear understanding of the structural mechanisms coupling GABA binding to anion-channel opening requires, at a minimum, the identification of the amino acid residues which form the binding site pocket for GABA. In addition, we are examining how mutations associated with human epilepsies alter GABAA receptor function. We are also interested in examining the assembly and trafficking of the receptor and how interactions with other proteins modulate GABAA receptor function.

Website:

http://www.physiology.wisc.edu/faculty/czajkowski.html

Selected Publications:

• Boileau, A.J., Pearce, R. A. and Czajkowski, C. (2010) The short splice variant of the γ2 subunit acts as an external modulator of GABAA receptor function. J. Neurosci. 30: 4895-4903 PMC Journal. In Process
• Wagoner, K.R. and Czajkowski, C. (2010) Stoichiometry of Expressed α4β2δ γ-aminobuytric acid type A receptors depends on the ratio of subunit unit cDNA transfected. J. Biol. Chem. 285: 14187-14194 PMC Journal – In Process
• Muroi, Y., C.M. Theusch, C. Czajkowski, and M. Jackson. 2009. Distinct structural changes in the GABA-A receptor elicited by pentobarbital and GABA. Biophys. J. 96: 499-509. In Process
• Hanson, S. M. and C. Czajkowski. 2008. Structural mechanisms underlying benzodiazepine modulation of the GABAA receptor. J. Neurosci. 28: 3490-3499.
• Mercado, J. and C. Czajkowski. 2008. GABA and pentobarbital induce different conformational rearrangements in the GABAA receptor a1 and b2 pre-M1 regions. J. Biol. Chem. 283: 15250-15257.
• Sharkey, L. M. and C. Czajkowski. 2008. Individually monitoring ligand-induced changes in the structure of the GABA-A receptor at benzodiazepine binding site and non-binding site interfaces. Mol. Pharmacol. 74: 1-10.
• Venkatachalan, S. and C. Czajkowski. 2008. A conserved salt-bridge critical for GABAA receptor function and loop C dynamics. PNAS 105: 13604-13609.
• Hanson, S.M., E.V. Morlock, K.A. Satyshur, and C. Czajkowski. 2008. Structural requirements for eszopiclone and zolpidem binding to the GABAA receptor are different. J. Med. Chem. 51: 7243-7252.
• Kloda, J. H. and C. Czajkowski. 2007. Agonist-, antagonist-, and benzodiazepine-induced structural changes in the a1Met113-Leu132 region of the GABA-A receptor. Mol. Pharmacol 71: 483-493.
• Sancar, F., S.S. Ericksen, A.M. Kucken, J.A. Teissere, and C. Czajkowski. 2007. Structural determinants for high affinity zolpidem binding to GABA-A receptors. Mol. Pharmacol 71: 38-46.
• Muroi, Y., C. Czajkowski, and M.B. Jackson. 2006. Local and global ligand-induced changes in the structure of the GABA-A receptor. Biochemistry 45: 7013-7022.
• Mercado, J. and C. Czajkowski. 2006. Charged residues in the a1 and b2 pre-M1 regions involved in GABA-A receptor activation. J. Neurosci. 26: 2031-2040.
• Boileau, A.J., R.A. Pearce, and C. Czajkowski. 2005. Tandem subunits effectively constrain GABA-A receptor stoichiometry and recapitulate receptor kinetics but are insensitive to GABA-A receptor-associated protein. J. Neurosci. 25: 11219-11230.
• Czajkowski, C. 2005. Triggers for channel opening. Nature 438: 167-168.
• Wagner, D.A., C. Czajkowski, and M.V. Jones. 2004. An arginine involved in GABA binding and unbinding but not gating of the GABAA receptor. J. Neurosci. 24: 2733-2741.
• Sancar, F. and C. Czajkowski. 2004. A GABAA receptor mutation linked to human epilepsy (g2 R43Q) impairs cell surface expression of abg receptors. J. Biol. Chem. 279: 47034-47039. [PDF]
• Newell, J.G., R.A. McDevitt, and C. Czajkowski. 2004. Mutation of glutamate 155 of the GABA-A receptor b2 subunit produces a spontaneously open channel: A trigger for channel activation. J. Neurosci. 24: 11226-11235.
• Boileau, A.J., T. Li, C. Benkwitz, C. Czajkowski, and R.A. Pearce. 2003. Effects of g2S subunit incorporation on GABAA receptormacroscopic kinetics. Neuropharmacology 44: 1003-1012.
• Newell, J.G. and C. Czajkowski. 2003. The GABAA receptor alpha1 subunit pro174-Asp191 segment is involved in GABA binding and channel gating. J. Biol. Chem.
• Kucken, A.M., J.A. Teissere, J. Seffinga-Clark, D.A. Wagner, and C. Czajkowski. 2003. Structural requirementsfor imidazobenzodiazepine binding to GABAA receptors. Mol. Pharmacol. 63: 289-296.
• Holden, J.H. and C. Czajkowski. 2002. Different residues in the GABAAreceptor alpha 1T60-alpha 1K70 region mediate GABA and SR-95531 actions. J. Biol. Chem. 277: 18785-18792.
• Bowser, D.N., D.A. Wagner, C. Czajkowski, B.A. Cromer, M.W. Parker, R.H. Wallace, L.A. Harkin, J.C. Mulley, C. Marini, S.F. Berkovic, D.A. Williams, M.V. Jones, and S. Petrou. 2002. Altered kinetics and benzodiazepine sensitivity of a GABAA receptorsubunit mutation [gamma 2(R43Q)] found in human epilepsy. Proc. Natl. Acad. Sci. U S A. 99: 15170-15175.
• Boileau, A.J., J.G. Newell, C. Czajkowski. 2002. GABAA receptor beta 2 Tyr97 and Leu99 line the GABA-binding site. Insights into mechanisms of agonist and antagonist actions. J. Biol. Chem. 277: 2931-2937.
• Boileau, A.J., R. Baur, L. Sharkey, E. Sigel, and C. Czajkowski. 2002. The relative amount of cRNA coding for gamma2 subunits affects stimulation by benzodiazepines in GABAA receptorsexpressed in Xenopus oocytes. Neuropharmacology 43: 695-700.
• Wagner, D.A. and C. Czajkowski. 2001. Structure and dynamics of the GABA binding pocket: a narrowing cleft that constricts during activation. J. Neurosci. 21: 67-74.
• Horenstein, J., D.A. Wagner, C. Czajkowski, and M.H. Akabas. 2001. Protein mobility and GABA-induced conformational changes detected in the GABAA receptor channel-lining M2 segment. Nat. Neurosci. 4: 477-485.
• Kucken, A.M., P. Ward, J.A. Teissere, D. Wagner, A.J. Boileau, and C. Czajkowski. 2000. Identification of benzodiazepine binding site residues on the g2 subunit of the GABAA receptor. Mol. Pharmacol. 57: 932-939.
• Boileau, A.J., A.R. Evers, A.F. Davis and C. Czajkowski. 1999. Mapping the agonist binding site of the GABAA receptor: evidence for a beta-strand. J. Neurosci. 19: 4847-4854.
• Boileau, A.J. and C. Czajkowski. 1999. Identification of transduction elements for benzodiazepine modulation of the GABAA receptor: three residues are required for allosteric coupling. J. Neurosci. 19: 10213-10220.