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- Aug 25, 2012
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Myostatin is a protein that limits muscle growth in tissues where it can be found in high concentrations. Proteins like this that act as signaling molecules between cells are called growth factors. Myostatin was formerly known as Growth and Differentiation Factor 8. It is made in muscle cells, then carried to other muscle cells through blood flow, attaching to specific receptors on their cellular membranes. Although the exact mechanism is unknown, this protein is somehow able to limit the development of muscle stem cells, cells responsible for differentiating into additional muscle cells, leading to a cap in muscle size.
Myostatin was discovered in 1997 when geneticists McPherron and Se-Jin Lee created "Mighty Mice" — mice lacking a certain gene and hence unable to produce this protein, possessing muscles about twice the size of those in normal mice. The researchers commented that they "look like Schwarzenegger mice." The gene associated with this substance has been found in the genomes of humans, mice, and zebrafish. Certain types of cattle have been selectively bred to have defective myostatin genes, leading to an increase in total size.
Several ligands that signal through the Activin type II receptors regulate muscle growth.[1] Myostatin, a TGF-beta superfamily member, is a negative regulator of muscle growth.[1] Myostatin binds to ACVR2B and to a lesser extent ACVR2A. In mice that were ACVR2A -/- (null) mutants there was an increase in all four muscle groups studied (pectoralis, triceps, quadriceps, and gastrocnemious/plantaris muscles).[1] Two of these muscle groups (pectoralis and triceps)were increased in ACVR2B -/- (null) mutants.[1] Activin plays a significant role in reproduction. ACVR2 receptors are present in the testis during testicular development.[2]
ACR2A and ACVR2B was found to be localized primarily in the gonocytes as well as in sertoli cells[2]. These cells are responsive to both autocrine and paracrine Activin B signaling, which controls their proliferation.[2] Cells of the epididymis also have ACVR2A receptors present. ACVR2B receptors were found to be localized in the rete testis.[2]
These two (technically three) proteins are why you need Follistatin, USA MYO HMP, and ACVR2B.
Myostatin was discovered in 1997 when geneticists McPherron and Se-Jin Lee created "Mighty Mice" — mice lacking a certain gene and hence unable to produce this protein, possessing muscles about twice the size of those in normal mice. The researchers commented that they "look like Schwarzenegger mice." The gene associated with this substance has been found in the genomes of humans, mice, and zebrafish. Certain types of cattle have been selectively bred to have defective myostatin genes, leading to an increase in total size.
Several ligands that signal through the Activin type II receptors regulate muscle growth.[1] Myostatin, a TGF-beta superfamily member, is a negative regulator of muscle growth.[1] Myostatin binds to ACVR2B and to a lesser extent ACVR2A. In mice that were ACVR2A -/- (null) mutants there was an increase in all four muscle groups studied (pectoralis, triceps, quadriceps, and gastrocnemious/plantaris muscles).[1] Two of these muscle groups (pectoralis and triceps)were increased in ACVR2B -/- (null) mutants.[1] Activin plays a significant role in reproduction. ACVR2 receptors are present in the testis during testicular development.[2]
ACR2A and ACVR2B was found to be localized primarily in the gonocytes as well as in sertoli cells[2]. These cells are responsive to both autocrine and paracrine Activin B signaling, which controls their proliferation.[2] Cells of the epididymis also have ACVR2A receptors present. ACVR2B receptors were found to be localized in the rete testis.[2]
These two (technically three) proteins are why you need Follistatin, USA MYO HMP, and ACVR2B.