This project focuses on a recently discovered crosstalk between two protein families: high-voltage-activated Ca2+ (CaV) channels and the Rem/Rad/Gem/Kir (RGK) family of Ras-like GTPases. Ca2+ influx through CaV channels (ICa) regulates many essential processes including muscle contraction, synaptic communication, and gene expression. Dysregulation of ICa is linked to diverse neurological and cardiovascular disorders including autism and cardiac arrhythmias. Conversely, blockade of ICa is an important therapy for serious diseases such as angina, stroke, and hypertension. RGK GTPases were recently revealed to potently inhibit CaV channels by interacting with auxiliary CaVbeta subunits. Because RGK proteins are widely prevalent, and their expression differentially regulated in disease, their crosstalk with CaV channels is well-placed to regulate many Ca2+-dependent biological and pathophysiological events. Moreover, RGK GTPases represent a new archetype of ICa inhibitors that could be potentially exploited to generate novel genetically-encoded CaV-channel blockers with therapeutic and practical applications. We seek to address critical unknowns related to the action of RGK GTPases on CaV channels that limit insights into the (patho)physiological impact of this crosstalk, and its latent beneficial exploitation. Our long-term objective is to gain an in-depth understanding of mechanisms underlying the RGK GTPase/CaV-channel crosstalk and apply this knowledge to: (1) an appreciation of how this interaction contributes to (patho)physiology, and (2) create a new generation of useful genetically-encoded CaV- channel inhibitors. We propose 3 Aims: (1) Clarify the impact of RGK proteins on the gating and trafficking of CaV channels and elucidate the underlying mechanisms. (2) Characterize the functional impact of Ca2+- CaM on the RGK GTPase/CaV channel crosstalk. (3) Determine the expression profile of RGK GTPases in heart and define the functional impact of their crosstalk with L-type CaV channels.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL084332-05
Application #
7787440
Study Section
Biophysics of Neural Systems Study Section (BPNS)
Program Officer
Przywara, Dennis
Project Start
2007-04-15
Project End
2012-03-31
Budget Start
2010-04-01
Budget End
2012-03-31
Support Year
5
Fiscal Year
2010
Total Cost
$402,500
Indirect Cost
Name
Columbia University (N.Y.)
Department
Physiology
Type
Schools of Medicine
DUNS #
621889815
City
New York
State
NY
Country
United States
Zip Code
10032
Puckerin, Akil A; Chang, Donald D; Shuja, Zunaira et al. (2018) Engineering selectivity into RGK GTPase inhibition of voltage-dependent calcium channels. Proc Natl Acad Sci U S A 115:12051-12056
Yang, Tingting; Colecraft, Henry M (2013) Regulation of voltage-dependent calcium channels by RGK proteins. Biochim Biophys Acta 1828:1644-54
Yang, Tingting; He, Lin-Ling; Chen, Ming et al. (2013) Bio-inspired voltage-dependent calcium channel blockers. Nat Commun 4:2540
Yang, Tingting; Puckerin, Akil; Colecraft, Henry M (2012) Distinct RGK GTPases differentially use ýý1- and auxiliary ýý-binding-dependent mechanisms to inhibit CaV1.2/CaV2.2 channels. PLoS One 7:e37079
Fang, Kun; Colecraft, Henry M (2011) Mechanism of auxiliary ýý-subunit-mediated membrane targeting of L-type (Ca(V)1.2) channels. J Physiol 589:4437-55
Xu, Xianghua; Marx, Steven O; Colecraft, Henry M (2010) Molecular mechanisms, and selective pharmacological rescue, of Rem-inhibited CaV1.2 channels in heart. Circ Res 107:620-30
Yang, Tingting; Xu, Xianghua; Kernan, Timothy et al. (2010) Rem, a member of the RGK GTPases, inhibits recombinant CaV1.2 channels using multiple mechanisms that require distinct conformations of the GTPase. J Physiol 588:1665-81
Xu, Xianghua; Colecraft, Henry M (2009) Engineering proteins for custom inhibition of Ca(V) channels. Physiology (Bethesda) 24:210-8