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Crystal structure of E. coli MlaFB ABC transport subunits in the dimeric state
Structural highlights
FunctionMLAB_ECOLI Part of the ABC transporter complex MlaFEDB, which is involved in a phospholipid transport pathway that maintains lipid asymmetry in the outer membrane by retrograde trafficking of phospholipids from the outer membrane to the inner membrane (PubMed:19383799, PubMed:27529189). MlaB plays critical roles in both the assembly and activity of the complex. May act by modulating MlaF structure and stability (PubMed:27529189).[1] [2] Publication Abstract from PubMedABC transporters facilitate the movement of diverse molecules across cellular membranes, but how their activity is regulated post-translationally is not well understood. Here we report the crystal structure of MlaFB from E. coli, the cytoplasmic portion of the larger MlaFEDB ABC transporter complex, which drives phospholipid trafficking across the bacterial envelope to maintain outer membrane integrity. MlaB, a STAS domain protein, binds the ABC nucleotide binding domain, MlaF, and is required for its stability. Our structure also implicates a unique C-terminal tail of MlaF in self-dimerization. Both the C-terminal tail of MlaF and the interaction with MlaB are required for the proper assembly of the MlaFEDB complex and its function in cells. This work leads to a new model for how an important bacterial lipid transporter may be regulated by small proteins, and raises the possibility that similar regulatory mechanisms may exist more broadly across the ABC transporter family. Structure of MlaFB uncovers novel mechanisms of ABC transporter regulation.,Kolich LR, Chang YT, Coudray N, Giacometti SI, MacRae MR, Isom GL, Teran EM, Bhabha G, Ekiert DC Elife. 2020 Jun 30;9:e60030. doi: 10.7554/eLife.60030. PMID:32602838[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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