MAPPING OF THE DOMAIN IN THE NEUROENDOCRINE PROTEIN 7B2 IMPORTANT FORITS HELPER FUNCTION TOWARDS PROHORMONE CONVERTASE PC2

In the secretory pathway, the neuroendocrine polypeptide 7B2 transient ly associates with its physiological target, the prohormone convertase PC2. The 7B2 protein carries two functional domains involved in the c ontrol of proPC2 maturation and activation, an inhibitory C-terminal r egion and an N-terminal domain displaying facilitative activity. Here, we show that a short segment in 7B2 (His(120)-Pro(131)) is important for its facilitative activity. Site-directed mutagenesis indicates tha t within this segment, Tyr(130) is particularly important for the abil ity of 7B2 to act as a helper protein for PC2. (C) 1998 Elsevier Scien ce Ireland Ltd. All rights reserved.