biostudies-literatureUnknown15Liao CH<h4>Background</h4>Hemin is a major source of iron for pathogens in infectious niches. The FecIRA-like surface signaling cascade is a common regulatory system for iron acquisition by pathogens. This system consists of a FecA-like TonB-dependent transporter (TBDT), a FecR-like inner membrane anti-sigma factor, and a FecI-like extracytoplasmic function (ECF) sigma factor. Beyond iron acquisition, FecIRA-like systems have been reported to regulate additional physiological processes. The known hemin acquisition system in <i>Stenotrophomonas maltophilia</i> includes HemA, a TBDT; HemU, an inner membrane transporter; and the TonB1-ExbB1-ExbD1a-ExbD1b complex, a multi-subunit motor that energizes HemA. Fur and HemP are the primary regulators involved in hemin utilization. In this study, we identiFrontiers in cellular and infection microbiology1722701https://www.ebi.ac.uk/biostudies/studies/S-EPMC12772443biostudies-literatureInvolvement of HemI, an ECF sigma factor, in hemin acquisition and antibiotic susceptibility in &lt;i&gt;Stenotrophomonas maltophilia&lt;/i&gt;.PMC12772443Li LHYang TCLu HFHu EWLiao CHKu RHfalseInvolvement of HemI, an ECF sigma factor, in hemin acquisition and antibiotic susceptibility in &lt;i&gt;Stenotrophomonas maltophilia&lt;/i&gt;.<h4>Background</h4>Hemin is a major source of iron for pathogens in infectious niches. The FecIRA-like surface signaling cascade is a common regulatory system for iron acquisition by pathogens. This system consists of a FecA-like TonB-dependent transporter (TBDT), a FecR-like inner membrane anti-sigma factor, and a FecI-like extracytoplasmic function (ECF) sigma factor. Beyond iron acquisition, FecIRA-like systems have been reported to regulate additional physiological processes. The known hemin acquisition system in <i>Stenotrophomonas maltophilia</i> includes HemA, a TBDT; HemU, an inner membrane transporter; and the TonB1-ExbB1-ExbD1a-ExbD1b complex, a multi-subunit motor that energizes HemA. Fur and HemP are the primary regulators involved in hemin utilization. In this study, we identi2025-01-01T00:00:00Z20252026-06-06T13:01:44.373Z2026-05-30T03:11:16.855ZS-EPMC127724434150303810.3389/fcimb.2025.1722701