The overall objectives are to elucidate the molecular structure, function and target recognition of a new family of neuronal calcium-binding proteins (CaBPs) that modulate the activity of neuronal calcium channels and are linked to various retinal and neurodegenerative diseases. The CaBP1 isoform interacts specifically with the inositol 1, 4, 5-trisphosphate (InsP3) receptor that serves as an important calcium release channel on the endoplasmic reticulum membrane. Defects in the regulation of neuronal InsP3 receptors promote excessive Ca2+ release, causing an overload of cytosolic Ca2+ that eventually results in neuronal cell death. Inhibition of InsP3 receptor activity by an endogenous inhibitory protein like CaBP1 or therapeutic agents that structurally mimic this inhibition will promote channel closure, which may prevent Ca2+-induced neuronal apoptosis and therefore could be an attractive way of slowing down the process of neurodegeneration. The long term goal of this research will be to determine the atomic-level structural basis for the regulation of InsP3 receptors by calcium and CaBP1. The work is divided into three specific aims:
The first aim i s to determine the structures of CaBP1 in solution by nuclear magnetic resonance and elucidate the calcium-induced conformational changes and structural determinants that underlie target recognition.
The second aim i s to measure the energetics and kinetics of calcium and target binding to CaBP1 and to probe Ca2+-dependent contacts between CaBP1 and the InsP3 receptor to help identify all regulatory regions involved in Ca2+-sensitive channel gating.
The third aim i s to determine the atomic- resolution structures of CaBP1 bound to the functional suppressor and ligand-binding domains in the InsP3 receptor. The structures will help identify important amino acid residues in these proteins that may be targeted in the rationale design of calcium channel inhibitory drugs.

Public Health Relevance

Calcium ion (Ca2+) in the cell is important for transmitting and regulating neural signals for normal brain function. The goal of our research is to understand how calcium sensor proteins in the brain and retina regulate the transport of cellular Ca2+ through ion channels during cell signaling.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS059969-02
Application #
7564748
Study Section
Biophysics of Neural Systems Study Section (BPNS)
Program Officer
Silberberg, Shai D
Project Start
2008-06-01
Project End
2012-05-31
Budget Start
2009-06-01
Budget End
2010-05-31
Support Year
2
Fiscal Year
2009
Total Cost
$225,527
Indirect Cost
Name
University of California Davis
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
047120084
City
Davis
State
CA
Country
United States
Zip Code
95618
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