PT  - JOURNAL ARTICLE
AU  - Thomas Cotton
AU  - Gerhard Fischer
AU  - Xuelu Wang
AU  - Jason McCoy
AU  - Magdalena Czepnik
AU  - Thomas B. Thompson
AU  - Marko Hyvönen
TI  - Structure of the human pro-myostatin precursor and determinants of growth factor latency
AID  - 10.1101/153403
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 153403
4099  - http://biorxiv.org/content/early/2017/06/23/153403.short
4100  - http://biorxiv.org/content/early/2017/06/23/153403.full
AB  - Myostatin, a key regulator of muscle mass in vertebrates, is biosynthesised as a latent precursor in muscle and is activated by sequential proteolysis of the pro-domain. To investigate the molecular mechanism by which pro-myostatin remains latent, we have solved the structure of unprocessed pro-myostatin and analysed the properties of the protein in its different forms. Crystal structures and SAXS analyses show that pro-myostatin adopts an open, V-shaped structure with a domain-swapped arrangement. The pro-mature complex, after cleavage of the furin site, has significantly reduced activity compared with mature growth factor and persists as a stable complex that is resistant to the natural antagonist follistatin. The latency appears to be conferred by a number of distinct features that collectively stabilise the interaction of the pro-domains with the mature growth factor, enabling a regulated step-wise activation process, distinct from the prototypical pro-TGF-β1. These results provide a basis for understanding the effect of missense mutations in pro-myostatin and pave the way for the design of novel myostatin inhibitors.