Cleavage cascade of the sigma regulator FecR orchestrates TonB-dependent signal transduction.

ABSTRACT: TonB-dependent signal transduction is a versatile mechanism observed in gram-negative bacteria that integrates energy-dependent substrate transport with signal relay. In Escherichia coli, the TonB-ExbBD motor complex energizes the TonB-dependent outer membrane transporter FecA, facilitating ferric citrate import. FecA also acts as a sensor, transmitting signals to the cytoplasmic membrane protein FecR, which eventually activates the cytoplasmic sigma factor FecI, driving transcription of the fec operon. Building on our previous finding that FecR undergoes functional maturation through a three-step cleavage process [T. Yokoyama et al., J. Biol. Chem. 296, 100673 (2021)], we here describe the complete mechanism of FecR-mediated ferric citrate signaling involving F

SUBMITTER: Yokoyama T 

PROVIDER: S-EPMC12036975 | biostudies-literature | 2025 Apr

REPOSITORIES: biostudies-literature