A proprotein convertase-inhibiting serpin with an endoplasmic reticulum targeting signal from Branchiostoma lanceolatum, a close relative of vertebrates.

ABSTRACT: Lancelets are considered to take a key position in the evolution of lineages leading to vertebrates. Herein, a serpin from the lancelet Branchiostoma lanceolatum, Bl-Spn1, was identified that inhibits the PCs (proprotein convertases) PC1/3 and furin. The inhibitor forms SDS-stable complexes with either of its targets. Analysis of the inhibitor/furin reaction products by mass spectroscopy assigns the enzyme's cleavage position C-terminally to Met-Met-Lys-Arg downward arrow in the reactive site loop of Spn1, in concordance with the classical recognition/cleavage site of the principal vertebrate PCs. The inhibitor is equipped with a canonical ER (endoplasmic reticulum) retrieval signal, Lys-Asp-Glu-Leu (KDEL), marking the inhibitor as a guardian of the cellular secretory routes. Deletion of t

SUBMITTER: Bentele C 

PROVIDER: S-EPMC1462704 | biostudies-literature | 2006 May

REPOSITORIES: biostudies-literature