ProSAAS (PCSK1N)

May be the control of the neuroendocrine secretory pathway. ProSAAS and Big PEN-LEN, both containing the C-terminal inhibitory domainname, but not the additional processed peptides reduce PCSK1 action in the endoplasmic reticulum and Golgi.

It lowers the action of the 84 kDa form but not the autocatalytically derived 66 kDa form of PCSK1. Subsequent processing of proSAAS may eliminate the inhibition.