FROM ACIDS TO OSMZ - MULTIPLE FACTORS INFLUENCE SYNTHESIS OF THE OMPFAND OMPC PORINS IN ESCHERICHIA-COLI

In Escherichia coil, levels of the two major outer membrane porin prot eins, OmpF and OmpC, are regulated in response to a variety of environ mental parameters, and numerous factors have been shown to influence p orin synthesis. EnvZ and OmpR control porin-gene transcription in resp onse to osmolarity, and the antisense RNA, MicF, influences ompF trans lation. In contrast to these characterized factors, some of the compon ents reported to influence porin expression have only modest effects a nd/or act indirectly. For others, potential regulatory roles, although intriguing, remain elusive. Here we review many of the components tha t have been reported to influence porin expression, address the potent ial regulatory nature of these components, and discuss how they may co ntribute to a regulatory network controlling porin synthesis.