SmiA is a hybrid priming/scaffolding adaptor for the LonA protease in Bacillus subtilis.

ABSTRACT: Regulatory proteolysis targets properly folded clients via a combination of cis-encoded degron sequences and trans-expressed specificity factors called adaptors. SmiA of Bacillus subtilis was identified as the first adaptor protein for the Lon family of proteases, but the mechanism of SmiA-dependent proteolysis is unknown. Here, we develop a fluorescence-based assay to measure the kinetics of SmiA-dependent degradation of its client SwrA and show that SmiA-SwrA interaction and the SwrA degron were both necessary, but not sufficient, for proteolysis. Consistent with a scaffolding adaptor mechanism, we found that stoichiometric excess of SmiA caused substrate-independent inhibition of LonA-dependent turnover. Furthermore, SmiA was strictly required even when SwrA levels were high suggesting

SUBMITTER: Olney SG 

PROVIDER: S-EPMC9204741 | biostudies-literature | 2022 Jul

REPOSITORIES: biostudies-literature