Voltage-gated calcium channels respond to changes in membrane potential and mediate the entry of calcium into many cell types where it serves as a second messenger to initiate intracellular regulatory and metabolic events. These channels are subject to complex regulation by hormones, neurotransmitters, and second messengers, and are the molecular target for several important classes of drugs. The skeletal muscle calcium channel has two physiological roles. Like calcium channels in other tissues, it mediates voltage-dependent calcium entry into the cytosol. It also serves as a voltage sensor for excitation-contraction coupling linking depolarization of the transverse tubule membrane to release of calcium from the sarcoplasmic reticulum via an unknown mechanism. The abundance of this calcium channel in skeletal muscle have made it a valuable model for studies of the molecular properties of calcium channels. In previous work, we have purified, reconstituted, determined the subunit structure, studied the regulation by protein phosphorylation, and identified 175 kDa and 212 kDa size forms of the principal alpha1 subunit of the skeletal muscle calcium channel. The studies proposed here will combine biochemical, molecular genetic, and electrophysiological approaches to define the functional properties of the individual calcium channel subunits and to establish the structure- function relationships for regulation of calcium channel ion conductance activity by post translational processing and subunit assembly and protein phosphorylation. We will define the carboxyl terminal amino acid sequence of the 175 kDa form of the alpha1 subunit and determine the localization of muscle fibers of its 212 kDa and 175 kDa forms. The ion conductance and regulatory properties of skeletal muscle calcium channels containing the 175 kDa and 212 kDa forms of the alpha1 subunit will be defined. The functional roles of the individual subunits of the calcium channel in expression of its ion conductance activity in mammalian somatic cells will be studied. Physiological sites of phosphorylation of skeletal muscle calcium channels will be identified and their role in regulation of ion conductance activity will be examined. This work will give molecular insight into the complex regulation of the ion conductance activity of this class of calcium channels and equally importantly, will provide a molecular basis for understanding the function and regulation of the L- type calcium channels which are expressed in much lower densities in neurons, cardiac cells.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS022625-06A1
Application #
3405275
Study Section
Physiology Study Section (PHY)
Project Start
1985-09-09
Project End
1995-06-30
Budget Start
1991-07-15
Budget End
1992-06-30
Support Year
6
Fiscal Year
1991
Total Cost
Indirect Cost
Name
University of Washington
Department
Type
Schools of Medicine
DUNS #
135646524
City
Seattle
State
WA
Country
United States
Zip Code
98195
Nanou, Evanthia; Lee, Amy; Catterall, William A (2018) Control of Excitation/Inhibition Balance in a Hippocampal Circuit by Calcium Sensor Protein Regulation of Presynaptic Calcium Channels. J Neurosci 38:4430-4440
Qian, Hai; Patriarchi, Tommaso; Price, Jennifer L et al. (2017) Phosphorylation of Ser1928 mediates the enhanced activity of the L-type Ca2+ channel Cav1.2 by the ?2-adrenergic receptor in neurons. Sci Signal 10:
Patriarchi, Tommaso; Qian, Hai; Di Biase, Valentina et al. (2016) Phosphorylation of Cav1.2 on S1928 uncouples the L-type Ca2+ channel from the ?2 adrenergic receptor. EMBO J 35:1330-45
Nanou, Evanthia; Scheuer, Todd; Catterall, William A (2016) Calcium sensor regulation of the CaV2.1 Ca2+ channel contributes to long-term potentiation and spatial learning. Proc Natl Acad Sci U S A 113:13209-13214
Tang, Lin; Gamal El-Din, Tamer M; Swanson, Teresa M et al. (2016) Structural basis for inhibition of a voltage-gated Ca2+ channel by Ca2+ antagonist drugs. Nature 537:117-121
Southan, Christopher; Sharman, Joanna L; Benson, Helen E et al. (2016) The IUPHAR/BPS Guide to PHARMACOLOGY in 2016: towards curated quantitative interactions between 1300 protein targets and 6000 ligands. Nucleic Acids Res 44:D1054-68
Nanou, Evanthia; Yan, Jin; Whitehead, Nicholas P et al. (2016) Altered short-term synaptic plasticity and reduced muscle strength in mice with impaired regulation of presynaptic CaV2.1 Ca2+ channels. Proc Natl Acad Sci U S A 113:1068-73
Nanou, Evanthia; Sullivan, Jane M; Scheuer, Todd et al. (2016) Calcium sensor regulation of the CaV2.1 Ca2+ channel contributes to short-term synaptic plasticity in hippocampal neurons. Proc Natl Acad Sci U S A 113:1062-7
Catterall, William A (2015) Finding Channels. J Biol Chem 290:28357-73
Yan, Jin; Leal, Karina; Magupalli, Venkat G et al. (2014) Modulation of CaV2.1 channels by neuronal calcium sensor-1 induces short-term synaptic facilitation. Mol Cell Neurosci 63:124-31

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