Calcium-dependent energetics of calmodulin domain interactions with regulatory regions of the Ryanodine Receptor Type 1 (RyR1)

Rhonda A Newman; Brenda R Sorensen; Adina M Kilpatrick; Madeline A Shea

doi:10.1016/j.bpc.2014.07.004

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Calcium-dependent energetics of calmodulin domain interactions with regulatory regions of the Ryanodine Receptor Type 1 (RyR1)

Journal article

Peer reviewed

Calcium-dependent energetics of calmodulin domain interactions with regulatory regions of the Ryanodine Receptor Type 1 (RyR1)

Rhonda A Newman, Brenda R Sorensen, Adina M Kilpatrick and Madeline A Shea

Biophysical chemistry, Vol.193-194, pp.35-49

09/2014

DOI: 10.1016/j.bpc.2014.07.004

PMCID: PMC4208696

PMID: 25145833

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Abstract

Calmodulin (CaM) allosterically regulates the homo-tetrameric human Ryanodine Receptor Type 1 (hRyR1): apo CaM activates the channel, while (Ca(2+))4-CaM inhibits it. CaM-binding RyR1 residues 1975-1999 and 3614-3643 were proposed to allow CaM to bridge adjacent RyR1 subunits. Fluorescence anisotropy titrations monitored the binding of CaM and its domains to peptides encompassing hRyR(11975-1999) or hRyR1(3614-3643). Both CaM and its C-domain associated in a calcium-independent manner with hRyR1(3614-3643) while N-domain required calcium and bound ~250-fold more weakly. Association with hRyR1(11975-1999) was weak. Both hRyR1 peptides increased the calcium-binding affinity of both CaM domains, while maintaining differences between them. These energetics support the CaM C-domain association with hRyR1(3614-3643) at low calcium, positioning CaM to respond to calcium efflux. However, the CaM N-domain affinity for hRyR(11975-1999) alone was insufficient to support CaM bridging adjacent RyR1 subunits. Other proteins or elements of the hRyR1 structure must contribute to the energetics of CaM-mediated regulation.

Thermodynamics

Apoproteins - chemistry

Protein Structure, Tertiary

Amino Acid Sequence

Calmodulin - genetics

Protein Structure, Secondary

Humans

Models, Molecular

Molecular Sequence Data

Recombinant Proteins - chemistry

Ryanodine Receptor Calcium Release Channel - chemical synthesis

Fluoresceins

Recombinant Proteins - genetics

Calcium - chemistry

Staining and Labeling

Ryanodine Receptor Calcium Release Channel - chemistry

Apoproteins - genetics

Protein Binding

Kinetics

Calmodulin - chemistry

Fluorescent Dyes

Details

Title: Subtitle: Calcium-dependent energetics of calmodulin domain interactions with regulatory regions of the Ryanodine Receptor Type 1 (RyR1)
Creators: Rhonda A Newman - Dept. of Biochemistry, Univ. of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242-1109, United States
Brenda R Sorensen - Dept. of Biochemistry, Univ. of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242-1109, United States
Adina M Kilpatrick - Department of Physics and Astronomy, Drake University, Des Moines, IA 50311-4516, United States
Madeline A Shea - Dept. of Biochemistry, Univ. of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242-1109, United States. Electronic address: madeline-shea@uiowa.edu
Resource Type: Journal article
Publication Details: Biophysical chemistry, Vol.193-194, pp.35-49
DOI: 10.1016/j.bpc.2014.07.004
PMID: 25145833
PMCID: PMC4208696
NLM abbreviation: Biophys Chem
ISSN: 0301-4622
eISSN: 1873-4200
Publisher: Elsevier BV; Netherlands
Grant note: NIH T32GM08365 / NIGMS NIH HHS R01 GM 57001 / NIGMS NIH HHS R01 GM057001 / NIGMS NIH HHS T32 GM008365 / NIGMS NIH HHS
Language: English
Date published: 09/2014
Academic Unit: Molecular Physiology and Biophysics; Iowa Neuroscience Institute; Biochemistry and Molecular Biology
Record Identifier: 9984025270302771

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