Met125 is essential for maintaining the structural integrity of calmodulin’s C-terminal domain

AbstractWe have used NMR and circular dichroism spectroscopy to investigate the structural and dynamic effects of oxidation on calmodulin (CaM), using peroxide and the Met to Gln oximimetic mutations. CaM is a Ca2+-sensitive regulatory protein that interacts with numerous targets. Due to its high methionine content, CaM is highly susceptible to oxidation by reactive oxygen species under conditions of cell stress and age-related muscle degeneration. CaM oxidation alters regulation of a host of CaM’s protein targets, emphasizing the importance of understanding the mechanism of CaM oxidation in muscle degeneration and overall physiology. It has been shown that the M125Q CaM mutant can mimic the functional effects of methionine oxidation on CaM’s regulation of the calcium release channel, ryanodine receptor (RyR). We report here that the M125Q mutation causes a localized unfolding of the C-terminal lobe of CaM, preventing the formation of a hydrophobic cluster of residues near the EF-hand Ca2+ binding sites. NMR analysis of CaM oxidation by peroxide offers further insights into the susceptibility of CaM’s Met residues to oxidation and the resulting structural effects. These results further resolve oxidation-driven structural perturbation of CaM, with implications for RyR regulation and the decay of muscle function in aging.

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Calcium channel ITPR2 and mitochondria–ER contacts promote cellular senescence and aging

Nature Communications ◽

10.1038/s41467-021-20993-z ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Dorian V. Ziegler ◽

David Vindrieux ◽

Delphine Goehrig ◽

Sara Jaber ◽

Guillaume Collin ◽

...

Keyword(s):

Cellular Senescence ◽

Calcium Release ◽

Liver Steatosis ◽

Metabolic Stress ◽

Calcium Release Channel ◽

Release Channel ◽

Age Related ◽

Trisphosphate Receptor

AbstractCellular senescence is induced by stresses and results in a stable proliferation arrest accompanied by a pro-inflammatory secretome. Senescent cells accumulate during aging, promoting various age-related pathologies and limiting lifespan. The endoplasmic reticulum (ER) inositol 1,4,5-trisphosphate receptor, type 2 (ITPR2) calcium-release channel and calcium fluxes from the ER to the mitochondria are drivers of senescence in human cells. Here we show that Itpr2 knockout (KO) mice display improved aging such as increased lifespan, a better response to metabolic stress, less immunosenescence, as well as less liver steatosis and fibrosis. Cellular senescence, which is known to promote these alterations, is decreased in Itpr2 KO mice and Itpr2 KO embryo-derived cells. Interestingly, ablation of ITPR2 in vivo and in vitro decreases the number of contacts between the mitochondria and the ER and their forced contacts induce premature senescence. These findings shed light on the role of contacts and facilitated exchanges between the ER and the mitochondria through ITPR2 in regulating senescence and aging.

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Cryo-electron microscopy and three-dimensional reconstruction of the calcium release channel/ryanodine receptor from skeletal muscle.

The Journal of Cell Biology ◽

10.1083/jcb.127.2.411 ◽

1994 ◽

Vol 127 (2) ◽

pp. 411-423 ◽

Cited By ~ 190

Author(s):

M Radermacher ◽

V Rao ◽

R Grassucci ◽

J Frank ◽

A P Timerman ◽

...

Keyword(s):

Skeletal Muscle ◽

Calcium Release ◽

Structural Integrity ◽

Three Dimensional ◽

Calcium Release Channel ◽

Density Region ◽

Release Channel ◽

Dimensional Reconstruction ◽

Triad Junction ◽

Cytoplasmic Assembly

The calcium release channel (CRC) from skeletal muscle is an unusually large tetrameric ion channel of the sarcoplasmic reticulum, and it is a major component of the triad junction, the site of excitation contraction coupling. The three-dimensional architecture of the CRC was determined from a random conical tilt series of images extracted from electron micrographs of isolated detergent-solubilized channels prepared in a frozen-hydrated state. Three major classes of fourfold symmetric images were identified, and three-dimensional reconstructions were determined for two of these. The two independent reconstructions were almost identical, being related to each other by a 180 degrees rotation about an axis in the plane of the specimen grid. The CRC consists of a large cytoplasmic assembly (29 x 29 x 12 nm) and a smaller transmembrane assembly that protrudes 7 nm from one of its faces. A cylindrical low-density region, 2-3 nm in apparent diameter, extends down the center of the transmembrane assembly, and possibly corresponds to the transmembrane Ca(2+)-conducting pathway. At its cytoplasmic end this channel-like feature appears to be plugged by a globular mass of density. The cytoplasmic assembly is apparently constructed from 10 or more domains that are loosely packed together such that greater than 50% of the volume enveloped by the assembly is occupied by solvent. The cytoplasmic assembly is suggestive of a scaffolding and seems well adapted to maintain the structural integrity of the triad junction while allowing ions to freely diffuse to and away from the transmembrane assembly.

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The calcium release channel of sarcoplasmic reticulum is modulated by FK-506-binding protein. Dissociation and reconstitution of FKBP-12 to the calcium release channel of skeletal muscle sarcoplasmic reticulum.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)49416-7 ◽

1993 ◽

Vol 268 (31) ◽

pp. 22992-22999 ◽

Cited By ~ 2

Author(s):

A.P. Timerman ◽

E Ogunbumni ◽

E Freund ◽

G Wiederrecht ◽

A.R. Marks ◽

...

Keyword(s):

Skeletal Muscle ◽

Sarcoplasmic Reticulum ◽

Calcium Release ◽

Binding Protein ◽

Calcium Release Channel ◽

Release Channel ◽

Fk 506 ◽

Protein Dissociation

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Modelling ionic conduction in the cardiac SR calcium-release channel under physiological and pathophysiological conditions

Journal of Molecular and Cellular Cardiology ◽

10.1016/0022-2828(92)93457-u ◽

1992 ◽

Vol 24 ◽

pp. 45 ◽

Cited By ~ 2

Author(s):

A TINKER

Keyword(s):

Calcium Release ◽

Ionic Conduction ◽

Calcium Release Channel ◽

Release Channel ◽

Sr Calcium Release

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Biphasic effects of doxorubicin on the calcium release channel from sarcoplasmic reticulum of cardiac muscle.

Circulation Research ◽

10.1161/01.res.67.5.1167 ◽

1990 ◽

Vol 67 (5) ◽

pp. 1167-1174 ◽

Cited By ~ 54

Author(s):

K Ondrias ◽

L Borgatta ◽

D H Kim ◽

B E Ehrlich

Keyword(s):

Sarcoplasmic Reticulum ◽

Cardiac Muscle ◽

Calcium Release ◽

Calcium Release Channel ◽

Release Channel

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Unravelling calcium-release channel gating: clues from a hot disease

Biochemical Journal ◽

10.1042/bj20040512 ◽

2004 ◽

Vol 380 (1) ◽

pp. e1-e3 ◽

Cited By ~ 1

Author(s):

Tommie V. McCARTHY ◽

John J. MACKRILL

Keyword(s):

Calcium Release ◽

Distinct Point ◽

Ryanodine Receptors ◽

Point Mutations ◽

Calcium Release Channel ◽

Release Channel ◽

Present Evidence ◽

Gating Mechanism ◽

Biochemical Journal ◽

Interdomain Interactions

Ryanodine receptors (RyRs) are a family of intracellular channels that mediate Ca2+ release from the endoplasmic and sarcoplasmic reticulum. More than 50 distinct point mutations in one member of this family, RyR1, cause malignant hyperthermia, a potentially lethal pharmacogenetic disorder of skeletal muscle. These mutations are not randomly distributed throughout the primary structure of RyR1, but are grouped in three discrete clusters. In this issue of the Biochemical Journal, Kobayashi et al. present evidence that interdomain interactions between two of these mutation-enriched regions play a key role in the gating mechanism of RyR1.

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