TY - JOUR
T1 - Identification of a protein complex that assembles lipopolysaccharide in the outer membrane of Escherichia coli
AU - Wu, Tao
AU - McCandlish, Andrew C.
AU - Gronenberg, Luisa S.
AU - Chng, Shu Sin
AU - Silhavy, Thomas J.
AU - Kahne, Daniel
PY - 2006/8/1
Y1 - 2006/8/1
N2 - The outer membrane of most Gram-negative bacteria is made up of LPS, and in nearly all bacteria that contain LPS it is essential for the life of the organism. The lipid portion of this molecule, lipid A, also known as endotoxin, is a potent activator of the innate immune response. More than 50 genes are required to synthesize LPS and assemble it at the cell surface. Enormous progress has been made in elucidating the structure and biosynthesis of LPS, but until recently the cellular components required for its transport from its site of synthesis in the inner membrane to its final cellular location at the cell surface remained elusive. Here we describe the identification of a protein complex that functions to assemble LPS at the surface of the cell. This complex contains two proteins: Imp, already identified as an essential outer-membrane protein implicated in LPS assembly; and another protein, RIpB, heretofore identified only as a rare lipoprotein. We show that RIpB is also essential for cell viability and that the Imp/RIpB complex is responsible for LPS reaching the outer surface of the outer membrane.
AB - The outer membrane of most Gram-negative bacteria is made up of LPS, and in nearly all bacteria that contain LPS it is essential for the life of the organism. The lipid portion of this molecule, lipid A, also known as endotoxin, is a potent activator of the innate immune response. More than 50 genes are required to synthesize LPS and assemble it at the cell surface. Enormous progress has been made in elucidating the structure and biosynthesis of LPS, but until recently the cellular components required for its transport from its site of synthesis in the inner membrane to its final cellular location at the cell surface remained elusive. Here we describe the identification of a protein complex that functions to assemble LPS at the surface of the cell. This complex contains two proteins: Imp, already identified as an essential outer-membrane protein implicated in LPS assembly; and another protein, RIpB, heretofore identified only as a rare lipoprotein. We show that RIpB is also essential for cell viability and that the Imp/RIpB complex is responsible for LPS reaching the outer surface of the outer membrane.
KW - Essential lipoprotein
KW - Gram-negative bacteria
KW - Outer-membrane biogenesis
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U2 - 10.1073/pnas.0604744103
DO - 10.1073/pnas.0604744103
M3 - Article
C2 - 16861298
AN - SCOPUS:33746852673
SN - 0027-8424
VL - 103
SP - 11754
EP - 11759
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 31
ER -