Mapping of the calpain proteolysis products of the junctional foot protein of the skeletal muscle triad junction

1992 ◽  
Vol 127 (1) ◽  
Author(s):  
NeilR Brandt ◽  
AnthonyH Caswell ◽  
Tara Brandt ◽  
Keith Brew ◽  
RonaldL Mellgren
Keyword(s):  
Skeletal Muscle ◽  
Triad Junction ◽  
Junctional Foot Protein

Molecular interactions of the junctional foot protein and dihydropyridine receptor in skeletal muscle triads

1990 ◽  
Vol 113 (3) ◽  
pp. 237-251 ◽  
Author(s):  
Neil R. Brandt ◽  
Anthony H. Caswell ◽  
Shu-Rong Wen ◽  
Jane A. Talvenheimo
Keyword(s):  
Skeletal Muscle ◽  
Molecular Interactions ◽  
Dihydropyridine Receptor ◽  
Junctional Foot Protein

Altered E-C coupling in triads isolated from malignant hyperthermia-susceptible porcine muscle

1995 ◽  
Vol 268 (6) ◽  
pp. C1381-C1386 ◽  
Author(s):  
R. el-Hayek ◽  
M. Yano ◽  
B. Antoniu ◽  
J. R. Mickelson ◽  
C. F. Louis ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Malignant Hyperthermia ◽  
Dihydropyridine Receptor ◽  
Normal Muscle ◽  
Direct Stimulation ◽  
Release Channel ◽  
Malignant Hyperthermia Susceptible ◽  
T Tubules ◽  
Junctional Foot Protein ◽  
Stimulation Of

Triad vesicles were isolated from normal (N) and homozygous malignant hyperthermia-susceptible (MHS) porcine skeletal muscle, and two types of sarcoplasmic reticulum Ca2+ release were investigated: 1) polylysine-induced Ca2+ release (direct stimulation of the junctional foot protein), and 2) depolarization-induced Ca2+ release (stimulation of the junctional foot protein via the dihydropyridine receptor). At submaximal concentrations of polylysine, the rates of induced Ca2+ release from the MHS triads were greater than from normal triads. The T tubules of polarized triads were depolarized by the K(+)-to-Na+ ionic replacement protocol. Higher grades of T-tubule depolarization resulted in higher rates of Ca2+ release from both MHS and normal triads but, when compared at a given grade of T-tubule depolarization, the release rate was always greater from the MHS than from normal triads. Thus the activity of the SR Ca2+ release channel is always higher in MHS than in normal muscle at a given submaximal dose of release trigger. This difference is observed when the channel is stimulated directly by polylysine or indirectly via a depolarization-induced activation of the T-tubule dihydropyridine receptor.

scholarly journals Deficiency of triad junction and contraction in mutant skeletal muscle lacking junctophilin type 1

2001 ◽  
Vol 154 (5) ◽  
pp. 1059-1068 ◽  
Author(s):  
Koichi Ito ◽  
Shinji Komazaki ◽  
Kazushige Sasamoto ◽  
Morikatsu Yoshida ◽  
Miyuki Nishi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Physiological Role ◽  
Mutant Mice ◽  
Functional Coupling ◽  
Release Channel ◽  
Signal Conversion ◽  
Triad Junction ◽  
Triad Junctions

In skeletal muscle excitation–contraction (E–C) coupling, the depolarization signal is converted from the intracellular Ca2+ store into Ca2+ release by functional coupling between the cell surface voltage sensor and the Ca2+ release channel on the sarcoplasmic reticulum (SR). The signal conversion occurs in the junctional membrane complex known as the triad junction, where the invaginated plasma membrane called the transverse-tubule (T-tubule) is pinched from both sides by SR membranes. Previous studies have suggested that junctophilins (JPs) contribute to the formation of the junctional membrane complexes by spanning the intracellular store membrane and interacting with the plasma membrane (PM) in excitable cells. Of the three JP subtypes, both type 1 (JP-1) and type 2 (JP-2) are abundantly expressed in skeletal muscle. To examine the physiological role of JP-1 in skeletal muscle, we generated mutant mice lacking JP-1. The JP-1 knockout mice showed no milk suckling and died shortly after birth. Ultrastructural analysis demonstrated that triad junctions were reduced in number, and that the SR was often structurally abnormal in the skeletal muscles of the mutant mice. The mutant muscle developed less contractile force (evoked by low-frequency electrical stimuli) and showed abnormal sensitivities to extracellular Ca2+. Our results indicate that JP-1 contributes to the construction of triad junctions and that it is essential for the efficiency of signal conversion during E–C coupling in skeletal muscle.

A Molecular Model of Excitation-Contraction Coupling at the Skeletal Muscle Triad Junction via Coassociated Oligomeric Calcium Channels

1989 ◽  
Vol 560 (1 Calcium Chann) ◽  
pp. 185-188 ◽  
Author(s):  
LIN HYMEL ◽  
HANSGEORG SCHINDLER ◽  
MAKOTO INUI ◽  
SIDNEY FLEISCHER ◽  
JÖRG STREISSNIG ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Calcium Channels ◽  
Molecular Model ◽  
Excitation Contraction Coupling ◽  
Contraction Coupling ◽  
Triad Junction

Proteins of the Triad Junction of Skeletal Muscle

1990 ◽  
pp. 361-369
Author(s):  
Anthony H. Caswell ◽  
Neil R. Brandt ◽  
Shu-Rong Wen ◽  
Jane A. Talvenheimo
Keyword(s):  
Skeletal Muscle ◽  
Triad Junction

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

1994 ◽  
Vol 127 (2) ◽  
pp. 411-423 ◽  
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.

scholarly journals The Role of Calpains in Skeletal Muscle Remodeling with Exercise and Inactivity-induced Atrophy

2020 ◽  
Vol 41 (14) ◽  
pp. 994-1008 ◽  
Author(s):  
Hayden W. Hyatt ◽  
Scott K. Powers
Keyword(s):  
Skeletal Muscle ◽  
Cell Signaling ◽  
Protein Turnover ◽  
Cysteine Proteases ◽  
Biologically Active ◽  
Membrane Repair ◽  
Downstream Signaling ◽  
Coupling Protein ◽  
Triad Junction ◽  
Muscle Remodeling

AbstractCalpains are cysteine proteases expressed in skeletal muscle fibers and other cells. Although calpain was first reported to act as a kinase activating factor in skeletal muscle, the consensus is now that calpains play a canonical role in protein turnover. However, recent evidence reveals new and exciting roles for calpains in skeletal muscle. This review will discuss the functions of calpains in skeletal muscle remodeling in response to both exercise and inactivity-induced muscle atrophy. Calpains participate in protein turnover and muscle remodeling by selectively cleaving target proteins and creating fragmented proteins that can be further degraded by other proteolytic systems. Nonetheless, an often overlooked function of calpains is that calpain-mediated cleavage of proteins can result in fragmented proteins that are biologically active and have the potential to actively influence cell signaling. In this manner, calpains function beyond their roles in protein turnover and influence downstream signaling effects. This review will highlight both the canonical and noncanonical roles that calpains play in skeletal muscle remodeling including sarcomere transformation, membrane repair, triad junction formation, regulation of excitation-contraction coupling, protein turnover, cell signaling, and mitochondrial function. We conclude with a discussion of key unanswered questions regarding the roles that calpains play in skeletal muscle.

scholarly journals Abnormal Features in Skeletal Muscle from Mice Lacking Mitsugumin29

1999 ◽  
Vol 147 (7) ◽  
pp. 1473-1480 ◽  
Author(s):  
Miyuki Nishi ◽  
Shinji Komazaki ◽  
Nagomi Kurebayashi ◽  
Yasuo Ogawa ◽  
Tetsuo Noda ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cell Surface ◽  
Membrane Structures ◽  
Intracellular Membranes ◽  
Transmembrane Segments ◽  
Membrane Complex ◽  
Junctional Complexes ◽  
Triad Junction ◽  
Normal Health

Physiological roles of the members of the synaptophysin family, carrying four transmembrane segments and being basically distributed on intracellular membranes including synaptic vesicles, have not been established yet. Recently, mitsugumin29 (MG29) was identified as a novel member of the synaptophysin family from skeletal muscle. MG29 is expressed in the junctional membrane complex between the cell surface transverse (T) tubule and the sarcoplasmic reticulum (SR), called the triad junction, where the depolarization signal is converted to Ca2+ release from the SR. In this study, we examined biological functions of MG29 by generating knockout mice. The MG29-deficient mice exhibited normal health and reproduction but were slightly reduced in body weight. Ultrastructural abnormalities of the membranes around the triad junction were detected in skeletal muscle from the mutant mice, i.e., swollen T tubules, irregular SR structures, and partial misformation of triad junctions. In the mutant muscle, apparently normal tetanus tension was observed, whereas twitch tension was significantly reduced. Moreover, the mutant muscle showed faster decrease of twitch tension under Ca2+-free conditions. The morphological and functional abnormalities of the mutant muscle seem to be related to each other and indicate that MG29 is essential for both refinement of the membrane structures and effective excitation-contraction coupling in the skeletal muscle triad junction. Our results further imply a role of MG29 as a synaptophysin family member in the accurate formation of junctional complexes between the cell surface and intracellular membranes.

Isolation of a terminal cisterna protein which may link the dihydropyridine receptor to the junctional foot protein in skeletal muscle

Biochemistry ◽  
1990 ◽  
Vol 29 (39) ◽  
pp. 9281-9289 ◽  
Author(s):  
Kyungsook C. Kim ◽  
Anthony H. Caswell ◽  
Jane A. Talvenheimo ◽  
Neil R. Brandt
Keyword(s):  
Skeletal Muscle ◽  
Dihydropyridine Receptor ◽  
Terminal Cisterna ◽  
Junctional Foot Protein
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