title: Latent myostatin has significant activity and this activity is controlled more efficiently by WFIKKN1 than by WFIKKN2.
abstract: Myostatin, a negative regulator of skeletal muscle growth, is produced from myostatin precursor by multiple steps of proteolytic processing. After cleavage by a furin-type protease, the propeptide and growth factor domains remain associated, forming a noncovalent complex, the latent myostatin complex. Mature myostatin is liberated from latent myostatin by bone morphogenetic protein 1/tolloid proteases. Here, we show that, in reporter assays, latent myostatin preparations have significant myostatin activity, as the noncovalent complex dissociates at an appreciable rate, and both mature and semilatent myostatin (a complex in which the dimeric growth factor domain interacts with only one molecule of myostatin propeptide) bind to myostatin receptor. The interaction of myostatin receptor with semilatent myostatin is efficiently blocked by WAP, Kazal, immunoglobulin, Kunitz and NTR domain-containing protein 1 or growth and differentiation factor-associated serum protein 2 (WFIKKN1), a large extracellular multidomain protein that binds both mature myostatin and myostatin propeptide [Kondás et al. (2008) J Biol Chem 283, 23677-23684]. Interestingly, the paralogous protein WAP, Kazal, immunoglobulin, Kunitz and NTR domain-containing protein 2 or growth and differentiation factor-associated serum protein 1 (WFIKKN2) was less efficient than WFIKKN1 as an antagonist of the interactions of myostatin receptor with semilatent myostatin. Our studies have shown that this difference is attributable to the fact that only WFIKKN1 has affinity for the propeptide domain, and this interaction increases its potency in suppressing the receptor-binding activity of semilatent myostatin. As the interaction of WFIKKN1 with various forms of myostatin permits tighter control of myostatin activity until myostatin is liberated from latent myostatin by bone morphogenetic protein 1/tolloid proteases, WFIKKN1 may have greater potential as an antimyostatic agent than WFIKKN2.
authors.affiliation: Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: György
authors.initials: G
authors.lastname: Szláma
authors.forename: Mária
authors.initials: M
authors.lastname: Trexler
authors.forename: László
authors.initials: L
authors.lastname: Patthy
mesh_terms: D030301:Activin Receptors, Type II / Q000378:metabolism*; D002352:Carrier Proteins; D002460:Cell Line; D017930:Genes, Reporter; D006801:Humans; D055767:Immobilized Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins; D007700:Kinetics; D055435:Myostatin / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D040081:Protein Array Analysis; D054730:Protein Interaction Domains and Motifs; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011498:Protein Precursors / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D059748:Proteolysis; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D055767:Immobilized Proteins; D036341:Intercellular Signaling Peptides and Proteins; C525911:MSTN protein, human; D055435:Myostatin; D010446:Peptide Fragments; D020033:Protein Isoforms; D011498:Protein Precursors; D011506:Proteins; D011994:Recombinant Proteins; C583826:WFIKKN1 protein, human; C424444:WFIKKN2 protein, human; D030301:Activin Receptors, Type II
keywords: WFIKKN1; WFIKKN2; latent myostatin; myostatin; promyostatin