This project studies G protein-gated inward rectifier K+ channels (GIRKs), continuing electrophysiological studies and also emphasizing biochemical studies of interactions between GIRKs and other molecules of signal transduction. (1) We shall address the physiological significance of the GIRK-integrin interaction. We shall study possible colocalization of the two molecules with confocal immunocytochemistry, study the identity of the integrin(s), and test for interactions between other inward rectifier K channels (non G protein-gated) and integrins. We shall test the hypothesis that the interaction also affects signal transduction by integrins. (2) We shall address the hypothesis that cells lacking normal RGS protein function will display postsynaptic responses. We shall study the detains of RGS action at the single-channel level, compare effects of RGS proteins on the kinetics of modulation at either GIRK or Ca/2+ channels, and use BIAcore measurements to address the hypothesis of ternary complexes among G proteins, RGS proteins, and GIRK channels. (3) We shall investigate surface exposure and topology of residues in GIRK channels using incorporated biocytin, domain structure and domain organization using site-specific nitrobenzyl-induced photochemical proteolysis of the main chain (SNIPP), and kinetic aspects of signal transduction using flash decaging of phosphorylatable tyrosine residues. (4) We shall investigate the hypothesis that the pathophysiology of the weaver mutation arises because of regenerative Na+ fluxes. We shall simultaneously conduct Ca2+ and Na+ imaging and electrophysiological investigations on weaver granule cells in culture following sudden activation of the GIRK channels. We shall investigate the hypothesis that some cells are spared because weaver channels appear in the cell membrane but are inactivated or inhibited. We shall attempt to understand the basis for activation by intracellular Na+. G protein-gated K+ channels (GIRKs) control the strength and frequency of the heartbeat, some responses to drugs of therapy and abuse, and some aspects of insulin secretion.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM029836-18
Application #
2761791
Study Section
Special Emphasis Panel (ZRG1-MDCN-3 (01))
Project Start
1981-04-01
Project End
2002-11-30
Budget Start
1998-12-01
Budget End
1999-11-30
Support Year
18
Fiscal Year
1999
Total Cost
Indirect Cost
Name
California Institute of Technology
Department
Type
Schools of Arts and Sciences
DUNS #
078731668
City
Pasadena
State
CA
Country
United States
Zip Code
91125
Lester, Henry A; Miwa, Julie M; Srinivasan, Rahul (2012) Psychiatric drugs bind to classical targets within early exocytotic pathways: therapeutic effects. Biol Psychiatry 72:907-15
Kovoor, Abraham; Seyffarth, Petra; Ebert, Jana et al. (2005) D2 dopamine receptors colocalize regulator of G-protein signaling 9-2 (RGS9-2) via the RGS9 DEP domain, and RGS9 knock-out mice develop dyskinesias associated with dopamine pathways. J Neurosci 25:2157-65
Rahman, Zia; Schwarz, Johannes; Gold, Stephen J et al. (2003) RGS9 modulates dopamine signaling in the basal ganglia. Neuron 38:941-52
Petersson, E James; Brandt, Gabriel S; Zacharias, Niki M et al. (2003) Caging proteins through unnatural amino acid mutagenesis. Methods Enzymol 360:258-73
Rozengurt, Nora; Lopez, Ivan; Chiu, Chi-Sung et al. (2003) Time course of inner ear degeneration and deafness in mice lacking the Kir4.1 potassium channel subunit. Hear Res 177:71-80
Tong, Y; Brandt, G S; Li, M et al. (2001) Tyrosine decaging leads to substantial membrane trafficking during modulation of an inward rectifier potassium channel. J Gen Physiol 117:103-18
Li, M; Lester, H A (2001) Ion channel diseases of the central nervous system. CNS Drug Rev 7:214-40
Neusch, C; Rozengurt, N; Jacobs, R E et al. (2001) Kir4.1 potassium channel subunit is crucial for oligodendrocyte development and in vivo myelination. J Neurosci 21:5429-38
Lester, H A; Karschin, A (2000) Gain of function mutants: ion channels and G protein-coupled receptors. Annu Rev Neurosci 23:89-125
Maurer, J A; Elmore, D E; Lester, H A et al. (2000) Comparing and contrasting Escherichia coli and Mycobacterium tuberculosis mechanosensitive channels (MscL). New gain of function mutations in the loop region. J Biol Chem 275:22238-44

Showing the most recent 10 out of 64 publications