Plays a role in cell envelope biogenesis, maintenance of cell envelope integrity and membrane homeostasis (PubMed:30368949, PubMed:33431434). Essential for lipoprotein maturation under conditions where membrane fluidity may be altered (PubMed:33431434). (Microbial infection) Involved in phage C1 and phage C6 infection (PubMed:8752353, PubMed:12558182). Participates in phage DNA transport pathways in cooperation with different outer membrane receptors, including FhuA and BtuB (PubMed:12558182). Is probably required in the second stage of phage adsorption, the DNA injection process. Participates in the formation or opening of diffusion channels through the outer membrane after phage adsorption (PubMed:12558182). DcrB probably only increases the efficiency of SdaC/DcrA action (PubMed:12558182). Disruption of the gene leads to phage C1 adsorption defect. Mutation does not impair vitamin B12 utilization (PubMed:8752353). Mutant is resistant to phage C6 (PubMed:12558182). Null mutant is not viable when grown at low temperatures, conditions which impact membrane fluidity (PubMed:33431434). Cells lacking both yciB and dcrB display pleiotropic defects, including morphological changes, elevated amounts of lipopolysaccharide, membrane vesiculation, reduced proton motive force, accumulation of outer membrane proteins at the inner membrane, and dynamic shrinking and extension of the cytoplasmic membrane accompanied by lysis and cell death (PubMed:30368949). Double mutant also displays a reduction in membrane fluidity and a marked sensitivity to copper ions (PubMed:33431434). It accumulates additional forms of Lpp and shows aberrant localization of Lpp due to inefficient lipid modification at the first step in lipoprotein maturation (PubMed:33431434). Belongs to the DcrB family. Extended N-terminus.