Calmodulin binding is dispensable for Rem-mediated Ca2+ channel inhibition

Robert N. Correll; Chunyan Pang; Dana M. Niedowicz; Jonathan Satin; Douglas A. Andres

doi:10.1007/s11010-007-9670-8

Calmodulin binding is dispensable for Rem-mediated Ca²⁺ channel inhibition

Robert N. Correll, Chunyan Pang, Dana M. Niedowicz, Jonathan Satin, Douglas A. Andres

Research output: Contribution to journal › Article › peer-review

5 Scopus citations

Abstract

GTPases of the Ras-related RGK family are negative regulators of high voltage-activated (HVA) Ca²⁺ channel activity. In this study, we examined the role of calmodulin (CaM) association in Rem-mediated Ca²⁺ channel inhibition. We found that the Rem/CaM interaction is Ca²⁺-dependent, and that truncation of the Rem C-terminus before position 277 prevents CaM binding. Serial mutagenesis of the Rem C-terminus between residues 265 and 276 to alanine generated two mutants (Rem^L271A and Rem^L274A) that displayed reduced CaM binding, and a subset of these mutants displayed significantly lower cell periphery localization than Rem^WT. However, reductions in CaM association or membrane trafficking did not affect function, as all Rem mutants could completely inhibit Ca²⁺ channels. The Rem^1-275 truncation mutant partially inhibited Ca²⁺ channel activity despite its inability to bind CaM. Taken together, these studies indicate that CaM association is not essential for either Rem-mediated Ca²⁺ channel inhibition or plasma membrane localization.

Original language	English
Pages (from-to)	103-110
Number of pages	8
Journal	Molecular and Cellular Biochemistry
Volume	310
Issue number	1-2
DOIs	https://doi.org/10.1007/s11010-007-9670-8
State	Published - Mar 2008

Bibliographical note

Funding Information:
Acknowledgments We wish to thank Dr. Carole Moncman for her assistance with the confocal imaging studies and statistical analysis, Dr. Thomas Vanaman for his gift of calmodulin-sepharose resin used in preliminary studies, and members of the Andres lab for critical reading of this manuscript. This work was supported by Public Health Service Grants HL072936 (to DAA), HL074091 (to JS), and P20 RR20171 from the National Center for Research Resources, National Institutes of Health (to DAA), and an American Heart Association pre-doctoral fellowship and an NIH Interdisciplinary Cardiovascular Training Grant T32 HL072743 (to RNC).

Keywords

Ca1.2
Calmodulin
L-type calcium channel
RGK
Ras
Rem GTPase
VDCC
Voltage-gated calcium channel

ASJC Scopus subject areas

Molecular Biology
Clinical Biochemistry
Cell Biology

Access to Document

10.1007/s11010-007-9670-8

Cite this

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title = "Calmodulin binding is dispensable for Rem-mediated Ca2+ channel inhibition",

abstract = "GTPases of the Ras-related RGK family are negative regulators of high voltage-activated (HVA) Ca2+ channel activity. In this study, we examined the role of calmodulin (CaM) association in Rem-mediated Ca2+ channel inhibition. We found that the Rem/CaM interaction is Ca2+-dependent, and that truncation of the Rem C-terminus before position 277 prevents CaM binding. Serial mutagenesis of the Rem C-terminus between residues 265 and 276 to alanine generated two mutants (RemL271A and RemL274A) that displayed reduced CaM binding, and a subset of these mutants displayed significantly lower cell periphery localization than RemWT. However, reductions in CaM association or membrane trafficking did not affect function, as all Rem mutants could completely inhibit Ca2+ channels. The Rem1-275 truncation mutant partially inhibited Ca2+ channel activity despite its inability to bind CaM. Taken together, these studies indicate that CaM association is not essential for either Rem-mediated Ca2+ channel inhibition or plasma membrane localization.",

keywords = "Ca1.2, Calmodulin, L-type calcium channel, RGK, Ras, Rem GTPase, VDCC, Voltage-gated calcium channel",

author = "Correll, {Robert N.} and Chunyan Pang and Niedowicz, {Dana M.} and Jonathan Satin and Andres, {Douglas A.}",

note = "Funding Information: Acknowledgments We wish to thank Dr. Carole Moncman for her assistance with the confocal imaging studies and statistical analysis, Dr. Thomas Vanaman for his gift of calmodulin-sepharose resin used in preliminary studies, and members of the Andres lab for critical reading of this manuscript. This work was supported by Public Health Service Grants HL072936 (to DAA), HL074091 (to JS), and P20 RR20171 from the National Center for Research Resources, National Institutes of Health (to DAA), and an American Heart Association pre-doctoral fellowship and an NIH Interdisciplinary Cardiovascular Training Grant T32 HL072743 (to RNC).",

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AU - Correll, Robert N.

AU - Pang, Chunyan

AU - Niedowicz, Dana M.

AU - Satin, Jonathan

AU - Andres, Douglas A.

N1 - Funding Information: Acknowledgments We wish to thank Dr. Carole Moncman for her assistance with the confocal imaging studies and statistical analysis, Dr. Thomas Vanaman for his gift of calmodulin-sepharose resin used in preliminary studies, and members of the Andres lab for critical reading of this manuscript. This work was supported by Public Health Service Grants HL072936 (to DAA), HL074091 (to JS), and P20 RR20171 from the National Center for Research Resources, National Institutes of Health (to DAA), and an American Heart Association pre-doctoral fellowship and an NIH Interdisciplinary Cardiovascular Training Grant T32 HL072743 (to RNC).

PY - 2008/3

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N2 - GTPases of the Ras-related RGK family are negative regulators of high voltage-activated (HVA) Ca2+ channel activity. In this study, we examined the role of calmodulin (CaM) association in Rem-mediated Ca2+ channel inhibition. We found that the Rem/CaM interaction is Ca2+-dependent, and that truncation of the Rem C-terminus before position 277 prevents CaM binding. Serial mutagenesis of the Rem C-terminus between residues 265 and 276 to alanine generated two mutants (RemL271A and RemL274A) that displayed reduced CaM binding, and a subset of these mutants displayed significantly lower cell periphery localization than RemWT. However, reductions in CaM association or membrane trafficking did not affect function, as all Rem mutants could completely inhibit Ca2+ channels. The Rem1-275 truncation mutant partially inhibited Ca2+ channel activity despite its inability to bind CaM. Taken together, these studies indicate that CaM association is not essential for either Rem-mediated Ca2+ channel inhibition or plasma membrane localization.

AB - GTPases of the Ras-related RGK family are negative regulators of high voltage-activated (HVA) Ca2+ channel activity. In this study, we examined the role of calmodulin (CaM) association in Rem-mediated Ca2+ channel inhibition. We found that the Rem/CaM interaction is Ca2+-dependent, and that truncation of the Rem C-terminus before position 277 prevents CaM binding. Serial mutagenesis of the Rem C-terminus between residues 265 and 276 to alanine generated two mutants (RemL271A and RemL274A) that displayed reduced CaM binding, and a subset of these mutants displayed significantly lower cell periphery localization than RemWT. However, reductions in CaM association or membrane trafficking did not affect function, as all Rem mutants could completely inhibit Ca2+ channels. The Rem1-275 truncation mutant partially inhibited Ca2+ channel activity despite its inability to bind CaM. Taken together, these studies indicate that CaM association is not essential for either Rem-mediated Ca2+ channel inhibition or plasma membrane localization.

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