93-kDa twin-domain serine protease inhibitor (Serpin) has a regulatory function on the beetle Toll proteolytic signaling cascade.

ABSTRACT: Serpins are protease inhibitors that play essential roles in the down-regulation of extracellular proteolytic cascades. The core serpin domain is highly conserved, and typical serpins are encoded with a molecular size of 35-50 kDa. Here, we describe a novel 93-kDa protein that contains two complete, tandemly arrayed serpin domains. This twin serpin, SPN93, was isolated from the larval hemolymph of the large beetle Tenebrio molitor. The N-terminal serpin domain of SPN93 forms a covalent complex with the Spätzle-processing enzyme, a terminal serine protease of the Toll signaling cascade, whereas the C-terminal serpin domain of SPN93 forms complexes with a modular serine protease and the Spätzle-processing enzyme-activating enzyme, which are two different enzymes of the cascade. Consequently,

SUBMITTER: Jiang R 

PROVIDER: S-EPMC3186399 | biostudies-literature | 2011 Oct

REPOSITORIES: biostudies-literature