Dynamics of triadin, a muscle-specific triad protein, within sarcoplasmic reticulum subdomains

Muriel Sébastien; Perrine Aubin; Jacques Brocard; Julie Brocard; Isabelle Marty; Julien Fauré

doi:10.1091/mbc.E19-07-0399

Dynamics of triadin, a muscle-specific triad protein, within sarcoplasmic reticulum subdomains

Mol Biol Cell. 2020 Feb 15;31(4):261-272. doi: 10.1091/mbc.E19-07-0399. Epub 2019 Dec 26.

Authors

Muriel Sébastien¹, Perrine Aubin¹, Jacques Brocard¹, Julie Brocard¹, Isabelle Marty¹, Julien Fauré^{1

2}

Affiliations

¹ Grenoble Institut Neurosciences, Inserm, U1216, University Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France.
² Grenoble Institut Neurosciences, Inserm, U1216, CHU Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France.

Abstract

In skeletal muscle, proteins of the calcium release complex responsible for the excitation-contraction (EC) coupling are exclusively localized in specific reticulum-plasma membrane (ER-PM) contact points named triads. The CRC protein triadin (T95) is localized in the sarcoplasmic reticulum (SR) subdomain of triads where it forms large multimers. However, the mechanisms leading to the steady-state accumulation of T95 in these specific areas of SR are largely unknown. To visualize T95 dynamics, fluorescent chimeras were expressed in triadin knockout myotubes, and their mobility was compared with the mobility of Sec61β, a membrane protein of the SR unrelated to the EC coupling process. At all stages of skeletal muscle cells differentiation, we show a permanent flux of T95 diffusing in the SR membrane. Moreover, we find evidence that a longer residence time in the ER-PM contact point is due to the transmembrane domain of T95 resulting in an overall triad localization.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Biological Transport
Cell Differentiation
Cell Membrane / metabolism
Cell Membrane / ultrastructure
Diffusion
Excitation Contraction Coupling / physiology
Gene Expression
Intracellular Signaling Peptides and Proteins / deficiency
Intracellular Signaling Peptides and Proteins / genetics*
Mice
Mice, Knockout
Muscle Contraction / physiology
Muscle Fibers, Skeletal / metabolism*
Muscle Fibers, Skeletal / ultrastructure
Muscle Proteins / deficiency
Muscle Proteins / genetics*
Muscle, Skeletal / cytology
Muscle, Skeletal / metabolism*
Muscle, Skeletal / ultrastructure
Ryanodine Receptor Calcium Release Channel / genetics*
Ryanodine Receptor Calcium Release Channel / metabolism
SEC Translocation Channels / genetics*
SEC Translocation Channels / metabolism
Sarcoplasmic Reticulum / metabolism*
Sarcoplasmic Reticulum / ultrastructure

Substances

Intracellular Signaling Peptides and Proteins
Muscle Proteins
Ryanodine Receptor Calcium Release Channel
SEC Translocation Channels
Trdn protein, mouse
ryanodine receptor 1, mouse