title: The subtilisin/kexin family of precursor convertases. Emphasis on PC1, PC2/7B2, POMC and the novel enzyme SKI-1.
abstract: Proopiomelanocortin (POMC) is a precursor to various, bioactive peptides including ACTH, beta LPH, alpha MSH, and beta endorphin (beta END). Processing of POMC at dibasic residues is tissue-specific and is performed by either PC1 alone (resulting in ACTH and beta LPH, anterior pituitary corticotrophes) or by a combination of PC1 and PC2 (yielding alpha MSH and beta END, pituitary neurointermediate lobe and hypothalamus). The PC2-specific binding protein 7B2 is intimately involved in the zymogen activation of proPC2 into PC2. Structure-function studies of these enzymes demonstrated the presence of N- and C-terminal domains, as well as specific amino acids within the catalytic segment that influence the degree of activity of each enzyme and the interaction of PC2 with 7B2. The tissue distribution, plasticity of expression, and the multiple precursors that are differentially cleaved by PC1 and/or PC2, predict a wide array of combinatorial activities of these convertases within the endocrine and neuroendocrine system. The phenotypic consequences of the absence of genetic expression of either PC1 or PC2 are now explored using knockout mice and in human patients suffering from obesity and diabetes.
authors.affiliation: Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, QC, Canada.
authors.forename: N G
authors.initials: NG
authors.lastname: Seidah
authors.forename: S
authors.initials: S
authors.lastname: Benjannet
authors.forename: J
authors.initials: J
authors.lastname: Hamelin
authors.forename: A M
authors.initials: AM
authors.lastname: Mamarbachi
authors.forename: A
authors.initials: A
authors.lastname: Basak
authors.forename: J
authors.initials: J
authors.lastname: Marcinkiewicz
authors.forename: M
authors.initials: M
authors.lastname: Mbikay
authors.forename: M
authors.initials: M
authors.lastname: Chrétien
authors.forename: M
authors.initials: M
authors.lastname: Marcinkiewicz
mesh_terms: D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000235:genetics* / Q000378:metabolism*; D003920:Diabetes Mellitus / Q000235:genetics; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009765:Obesity / Q000235:genetics; D010902:Pituitary Gland / Q000201:enzymology; D011333:Pro-Opiomelanocortin / Q000235:genetics* / Q000378:metabolism*; D045664:Proprotein Convertase 1; D043484:Proprotein Convertases; D011499:Protein Processing, Post-Translational; D029701:Saccharomyces cerevisiae Proteins; D012867:Skin / Q000201:enzymology; D013381:Subtilisins / Q000235:genetics / Q000378:metabolism*
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D011333:Pro-Opiomelanocortin; D043484:Proprotein Convertases; D013381:Subtilisins; C058751:KEX2 protein, S cerevisiae; C473656:Pcsk1 protein, mouse; D045664:Proprotein Convertase 1; D016282:Aspartic Acid Endopeptidases