Merck
  • Home
  • Search Results
  • ERK1/2 inhibition promotes robust myotube growth via CaMKII activation resulting in myoblast-to-myotube fusion.

ERK1/2 inhibition promotes robust myotube growth via CaMKII activation resulting in myoblast-to-myotube fusion.

Developmental cell (2021-12-22)
Tamar Eigler, Giulia Zarfati, Emmanuel Amzallag, Sansrity Sinha, Nadav Segev, Yishaia Zabary, Assaf Zaritsky, Avraham Shakked, Kfir-Baruch Umansky, Eyal D Schejter, Douglas P Millay, Eldad Tzahor, Ori Avinoam
ABSTRACT

Myoblast fusion is essential for muscle development and regeneration. Yet, it remains poorly understood how mononucleated myoblasts fuse with preexisting fibers. We demonstrate that ERK1/2 inhibition (ERKi) induces robust differentiation and fusion of primary mouse myoblasts through a linear pathway involving RXR, ryanodine receptors, and calcium-dependent activation of CaMKII in nascent myotubes. CaMKII activation results in myotube growth via fusion with mononucleated myoblasts at a fusogenic synapse. Mechanistically, CaMKII interacts with and regulates MYMK and Rac1, and CaMKIIδ/γ knockout mice exhibit smaller regenerated myofibers following injury. In addition, the expression of a dominant negative CaMKII inhibits the formation of large multinucleated myotubes. Finally, we demonstrate the evolutionary conservation of the pathway in chicken myoblasts. We conclude that ERK1/2 represses a signaling cascade leading to CaMKII-mediated fusion of myoblasts to myotubes, providing an attractive target for the cultivated meat industry and regenerative medicine.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
DAPI, for nucleic acid staining
Sigma-Aldrich
Anti-MAP Kinase (ERK-1, 351-368) antibody produced in rabbit, IgG fraction of antiserum, buffered aqueous solution
Sigma-Aldrich
Anti-MAP Kinase, Activated (Diphosphorylated ERK-1&2) antibody, Mouse monoclonal, clone MAPK-YT, purified from hybridoma cell culture
Sigma-Aldrich
Anti-phospho-Rac1/cdc42 (Ser71) Antibody, from rabbit, purified by affinity chromatography
Sigma-Aldrich
Anti-MAP Kinase (ERK-1, ERK-2) antibody produced in rabbit, whole antiserum
Sigma-Aldrich
Phosphatase Inhibitor Cocktail 2, aqueous solution (dark coloration may develop upon storage, which does not affect the activity)
Sigma-Aldrich
Protease Inhibitor Cocktail, for use with mammalian cell and tissue extracts, DMSO solution
Sigma-Aldrich
Phosphatase Inhibitor Cocktail 3, DMSO solution
Sigma-Aldrich
Anti-phospho-CaMK2 (pThr286) antibody produced in rabbit, affinity isolated antibody
Sigma-Aldrich
Anti-Rac1 Antibody, clone 23A8, clone 23A8, Upstate®, from mouse