Premium
Structure and expression of Xenopus prohormone convertase PC2
Author(s) -
Braks Joanna A.M.,
Guldemond Karin C.W.,
van Riel Maarten C.H.M.,
Coenen Anton J.M.,
Martens Gerard J.M.
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80652-w
Subject(s) - xenopus , proopiomelanocortin , prohormone , prohormone convertase , biology , melanocyte stimulating hormone , peptide sequence , amino acid , signal peptide , gene expression , endocrinology , medicine , microbiology and biotechnology , biochemistry , hormone , gene
The multifunctional prohormone, proopiomelanocortin (POMC), is processed in the melanotrope cells of the pituitary pars intermedia at pairs of basic amino acid residues to give a number of peptides, including α‐melanophore‐stimulating hormone (α‐MSH). This hormone causes skin darkening in amphibians during background adaptation. Here we report the complete structure of Xenopus laevis prohormone convertase PC2, the enzyme thought to be responsible for processing of POMC to α‐MSH. A comparative structural analysis revealed an overall amino acid sequence identity of 85–87% between Xenopus PC2 and its mammalian counterparts, with the lowest degree of identity in the signal peptide sequence (28–36%) and the region amino‐terminal to the catalytic domain (59–60%). The occurrence of a second, structurally different PC2 protein reflects the expression of two Xenopus PC2 genes. The expression pattern of PC2 in the Xenopus pituitary gland of black‐ and white‐adapted animals was found to be similar to that of POMC, namely high expression in active melanotrope cells of black animals. This observation is in line with a physiological role for PC2 in processing POMC to α‐MSH.