MCE domain proteins: conserved inner membrane lipid-binding proteins required for outer membrane homeostasis

Journal article

AbstractBacterial proteins with MCE domains were first described as being important for Mammalian Cell Entry. More recent evidence suggests they are components of lipid ABC transporters. In Escherichia coli, the single-domain protein MlaD is known to be part of an inner membrane transporter that is important for maintenance of outer membrane lipid asymmetry. Here we describe two multi MCE domain-containing proteins in Escherichia coli, PqiB and YebT, the latter of which is an orthologue of MAM-7 that was previously reported to be an outer membrane protein. We show that all three MCE domain-containing proteins localise to the inner membrane. Bioinformatic analyses revealed that MCE domains are widely distributed across bacterial phyla but multi MCE domain-containing proteins evolved in Proteobacteria from single-domain proteins. Mutants defective in mlaD, pqiAB and yebST were shown to have distinct but partially overlapping phenotypes, but the primary functions of PqiB and YebT differ from MlaD. Complementing our previous findings that all three proteins bind phospholipids, results presented here indicate that multi-domain proteins evolved in Proteobacteria for specific functions in maintaining cell envelope homeostasis.

Authors: Isom, GL; Davies, NJ; Chong, Z-S; Bryant, JA; Jamshad, M

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Nature Research
• Journal: Scientific Reports
• Volume: 7
• Issue: 1
• Pages: 8608-8608
• Publication date: 2017-08-11
• DOI: 10.1038/s41598-017-09111-6
• EISSN: 2045-2322
• ISSN: 2045-2322
• Language: English
• Keywords: Membrane; Transport protein; FERM domain; Cell biology; Gene; Biochemistry; Bacterial outer membrane; Membrane protein; Peripheral membrane protein; Integral membrane protein; Protein domain; Membrane transport protein; Inner membrane; Biology; Escherichia coli; Cell envelope