p24 Proteins from the same subfamily are functionally nonredundant.
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 (p24α(3), -β(1), -γ(3), -δ(2)) is upregulated coordinately with the major melanotrope cargo, proopiomelanocortin (POMC), whereas two other p24s (p24γ(2) and -δ(1)) are also expressed, but not coordinately with POMC. Using melanotrope-specific transgene expression, we here find that the roles of both p24γ(2) and p24δ(1) in the transport, glycosylation, sulphation and cleavage of POMC are different from those of their upregulated subfamily relatives (p24γ(3) and p24δ(2), respectively). Thus, even p24 proteins from the same subfamily have distinct functions in secretory cargo biosynthesis.
Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, and Nijmegen Centre for Molecular Life Sciences (NCMLS), 282 Department of Molecular Animal Physiology, Radboud University Nijmegen, Geert Grooteplein Zuid 28, Nijmegen, The Netherlands.
Jeroen R P M
JR
Strating
Gerrit
G
Bouw
Theo G M
TG
Hafmans
Gerard J M
GJ
Martens
D000818:Animals; D052717:Melanotrophs / Q000378:metabolism; D011333:Pro-Opiomelanocortin / Q000096:biosynthesis / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D019076:Transgenes / Q000235:genetics; D033921:Vesicular Transport Proteins / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D029867:Xenopus Proteins / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis
D033921:Vesicular Transport Proteins; D029867:Xenopus Proteins; D011333:Pro-Opiomelanocortin