Myostatin (GDF-8) is a key factor in linking muscle mass and skeletal structure.

Myostatin (GDF-8) is a member of the transforming growth factor-beta (TFF-beta) superfamily, which is highly expressed in skeletal muscle. Loss of myostatin function leads to skeletal muscle mass. double. Myostatin-deficient mice were used as models to study muscle-skeletal interactions, and here we review the bone phenotype associated with changes in the myostatin signaling pathway. It is known that myostatin is a key regulator of proliferation and differentiation of mesenchymal stem cells, and the body fat lacking myostatin gene is reduced, and bone density and strength are generally increased. An increase in bone density can be observed in most anatomical regions, including the extremities, spine, and mandible, and myostatin inhibitors have been observed to significantly increase bone formation. Myostatin is also expressed early in fracture healing, and the lack of myostatin leads to an increase in the size and strength of fracture callus. Taken together, these data indicate that myostatin has a direct effect on the proliferation and differentiation of osteoprogenitor cells, and myostatin antagonists and inhibitors may simultaneously increase muscle mass and bone strength.

Discovery and sequencing

In 1997, geneticists Se-Jin Lee and Alexandra McPherron discovered genes encoding myostatin, and they developed a knock-out mouse with a gene deletion. The muscle mass of this mouse is about normal mice. Twice. These mice were later called “big mice.”

Natural defects in various myostatins have been found in cattle, sheep, whippets and certain species of humans. In each case, the result is a dramatic increase in muscle mass.

Behavioral structure and mechanism

Human myostatin consists of two identical subunits, each consisting of 109 amino acid residues (the NCBI database claims 375 residues of human myostatin). The total molecular weight is 25.0 kDa. The protein is inactive prior to the nh2 terminus or “pre-domain” portion of the protease cleavage molecule, thereby forming an active cooh terminal dimer. Myostatin binds to the activin II receptor, resulting in the recruitment of the core receptor Alk-3 or Alk-4. This coreceptor then initiates a cellular signaling cascade in the muscle, including activation of the transcription factors SMAD2 and SMAD3 in the SMAD family. These factors then induce myostatin-specific gene regulation. When applied to myoblasts, myostatin inhibits their differentiation into mature muscle fibers.

Myostatin also inhibits Akt, a kinase that is sufficient to cause muscle hypertrophy, in part by activating protein synthesis. However, Akt is not the overall cause of all the effects of muscle hypertrophy mediated by inhibition of myostatin. Therefore, myostatin acts in two ways: inhibition of muscle differentiation and inhibition of Akt-induced protein synthesis.

How does it work?

Myostatin propeptides promote muscle and bone regeneration by blocking the activity of recombinant myostatin. Myostatin inhibitors improve wound healing in deep penetrating lesions of muscles and bones.