TY - JOUR
T1 - Signal sequence processing is required for the assembly of lamB trimers in the outer membrane of Escherichia coli
AU - Carlson, J. H.
AU - Silhavy, T. J.
PY - 1993
Y1 - 1993
N2 - Proteins destined for either the periplasm or the outer membrane of Escherichia coli are translocated from the cytoplasm by a common mechanism. It is generally assumed that outer membrane proteins, such as LamB (maltoporin or λ receptor), which are rich in β-structure, contain additional targeting information that directs proper membrane insertion. During transit to the outer membrane, these proteins may pass, in soluble form, through the periplasm or remain membrane associated and reach their final destination via sites of inner membrane-outer membrane contact (zones of adhesion). We report lamB mutations that slow signal sequence cleavage, delay release of the protein from the inner membrane, and interfere with maltoporin biogenesis. This result is most easily explained by proposing a soluble, periplasmic LamB assembly intermediate. Additionally, we found that such lamB mutations confer several novel phenotypes consistent with an abortive attempt by the cell to target these tethered LamB molecules. These phenotypes may allow isolation of mutants in which the process of outer membrane protein targeting is altered.
AB - Proteins destined for either the periplasm or the outer membrane of Escherichia coli are translocated from the cytoplasm by a common mechanism. It is generally assumed that outer membrane proteins, such as LamB (maltoporin or λ receptor), which are rich in β-structure, contain additional targeting information that directs proper membrane insertion. During transit to the outer membrane, these proteins may pass, in soluble form, through the periplasm or remain membrane associated and reach their final destination via sites of inner membrane-outer membrane contact (zones of adhesion). We report lamB mutations that slow signal sequence cleavage, delay release of the protein from the inner membrane, and interfere with maltoporin biogenesis. This result is most easily explained by proposing a soluble, periplasmic LamB assembly intermediate. Additionally, we found that such lamB mutations confer several novel phenotypes consistent with an abortive attempt by the cell to target these tethered LamB molecules. These phenotypes may allow isolation of mutants in which the process of outer membrane protein targeting is altered.
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U2 - 10.1128/jb.175.11.3327-3334.1993
DO - 10.1128/jb.175.11.3327-3334.1993
M3 - Article
C2 - 8501036
AN - SCOPUS:0027285690
SN - 0021-9193
VL - 175
SP - 3327
EP - 3334
JO - Journal of bacteriology
JF - Journal of bacteriology
IS - 11
ER -