The complexities of porin genetic regulation.
Our understanding of porin regulation has revealed not only increasing complexity in the regulatory mechanisms, but also that the porin repertoire is more extensive than previously conceived. Initially, the OmpR response regulator was described as the master regulator of porin genes, but many more regulators are involved such as CpxR, PhoB, Lrp, Rob, MarA, SoxS, CadC, CRP, Fnr, ToxR, H-NS, StpA, IHF, HU and LeuO. In addition to MicF, the first small RNA (sRNA) that was proposed to regulate porin expression, porins are post-transcriptionally regulated by a variety of other sRNAs, namely, MicC, MicA, IpeX, RseX, InvR, CyaR and RybB. Future challenges include the full integration of all the regulatory circuitries. Whether quiescent porins are merely replacements of the major porins or are part of novel metabolic programs has yet to be elucidated. The comprehensive exploration of the environmental determinants that affect porin gene expression should yield valuable new information about the functions of these important proteins.
De la Cruz
Miguel Angel
MA
Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México.
Calva
Edmundo
E
D004926:Escherichia coli / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D018272:Porins / Q000096:biosynthesis* / Q000235:genetics*; D034741:RNA, Small Interfering / Q000235:genetics / Q000502:physiology; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology; D019779:Salmonella enterica / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology
D018272:Porins; D034741:RNA, Small Interfering; D012097:Repressor Proteins; D014157:Transcription Factors