p24 Proteins from the same subfamily are functionally nonredundant

Item does not contain fulltext The p24 proteins function in early secretory pathway transport processes, but their exact role is unclear. In physiologically activated Xenopus melanotrope cells, a representative of each p24 subfamily (p24alpha(3), -beta(1), -gamma(3), -delta(2)) is upregulated coordinately with the major melanotrope cargo, proopiomelanocortin (POMC), whereas two other p24s (p24gamma(2) and -delta(1)) are also expressed, but not coordinately with POMC. Using melanotrope-specific transgene expression, we here find that the roles of both p24gamma(2) and p24delta(1) in the transport, glycosylation, sulphation and cleavage of POMC are different from those of their upregulated subfamily relatives (p24gamma(3) and p24delta(2), respectively). Thus, even p24 proteins from the same subfamily have distinct functions in secretory cargo biosynthesis. 01 maart 2011