How proteins cross the bacterial cytoplasmic membrane

Driessen, Arnold J. M.

doi:10.1007/bf00234937

Cited by 61 publications

(50 citation statements)

References 175 publications

(239 reference statements)

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“…The 10 transmembrane structures and orientation of membrane anchors of Sec61p are similar to the topological model proposed for the SecY subunit of the bacterial cytoplasmic membrane translocase (54). SecY has been widely implicated in protein translocation across the cytoplasmic membrane of E. coli (55) and appears to be distantly related to Sec61p (56). The hydrophobic segments in Sec61p vary enormously in their length and relative mean hydropathies (Fig.…”

Section: Discussionsupporting

confidence: 54%

Determination of the Transmembrane Topology of Yeast Sec61p, an Essential Component of the Endoplasmic Reticulum Translocation Complex

Wilkinson

Critchley

Stirling

1996

Journal of Biological Chemistry

142

147

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Sec61p is a highly conserved integral membrane protein that plays a role in the formation of a proteinconducting channel required for the translocation of polypeptides into, and across, the membrane of the endoplasmic reticulum. As a major step toward elucidating the structure of the endoplasmic reticulum translocation apparatus, we have determined the transmembrane topology of Sec61p using a combination of C-terminal reporter-domain fusions and the in situ digestion of specifically inserted factor Xa protease cleavage sites. Our data indicate the presence of 10 transmembrane domains, including several with surprisingly limited hydrophobicity. Furthermore, we provide evidence for complex intramolecular interactions in which these weakly hydrophobic domains require C-terminal sequences for their correct topogenesis. The incorporation of sequences with limited hydrophobicity into the bilayer may play a vital role in the formation of an aqueous membrane channel required for the translocation of hydrophilic polypeptide chains.

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Section: Discussionsupporting

confidence: 54%

Determination of the Transmembrane Topology of Yeast Sec61p, an Essential Component of the Endoplasmic Reticulum Translocation Complex

Wilkinson

Critchley

Stirling

1996

Journal of Biological Chemistry

142

147

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“…Protein translocation across the Escherichia coli cytoplasmic membrane is catalysed by a machinery comprising six Sec factors, A, D, E, F, G and Y and is assisted by a molecular chaperone, SecB (for reviews see Schatz and Beckwith, 1990;Pugsley, 1993;Driessen, 1994;Tokuda, 1994;Ito, 1996;. SecY and SecE had been thought to form a protein-conducting channel in the membrane through which the translocation of the precursor takes place in an ATP-dependent manner.…”

Section: Introductionmentioning

confidence: 99%

Coupled structure change of SecA and SecG revealed by the synthetic lethality of the secAcsR11 and ΔsecG::kan double mutant

Suzuki

Nishiyama

Tokuda

1998

Molecular Microbiology

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SummaryAn Escherichia coli strain carrying either the secAcsR11 or ⌬secG::kan mutation is unable to grow at low temperature owing to cold-sensitive protein translocation but grows normally at 37ЊC. However, introduction of the two mutations into the same cells caused a severe defect in protein translocation and the cells were unable to grow at any temperature examined, indicating that secG is essential for the secAcsR11 mutant. The mutant SecA (csSecA) was found to possess a single amino acid substitution in the precursor-binding region and was defective in the interaction with the precursor protein. Furthermore, the membrane insertion of SecA and the membrane topology inversion of SecG, both of which took place upon the initiation of protein translocation, were significantly retarded even at 37ЊC, when csSecA was used instead of the wild-type SecA. The insertion of the wild-type SecA was also significantly defective when SecG-depleted membrane vesicles were used in place of SecG-containing ones. No insertion of csSecA occurred into SecG-depleted membrane vesicles. Examination of in vitro protein translocation at 37ЊC revealed that SecG is essential for csSecAdependent protein translocation. We conclude that SecG and SecA undergo a coupled structure change, that is critical for efficient protein translocation.

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“…First, they are required for protein targeting to and translocation across membranes, such as the eubacterial plasma membrane and the endoplasmic reticular membrane of eukaryotes (for reviews, see Refs. [1][2][3][4]. Second, in addition to their role as determinants for protein targeting and translocation, certain signal peptides have a signaling function.…”

mentioning

confidence: 99%

Signal Peptide Peptidase- and ClpP-like Proteins of Bacillus subtilis Required for Efficient Translocation and Processing of Secretory Proteins

Bolhuis¹,

Matzen

Hyyryläinen

et al. 1999

Journal of Biological Chemistry

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Signal peptides direct the export of secretory proteins from the cytoplasm. After processing by signal peptidase, they are degraded in the membrane and cytoplasm. The resulting fragments can have signaling functions. These observations suggest important roles for signal peptide peptidases. The present studies show that the Gram-positive eubacterium Bacillus subtilis contains two genes for proteins, denoted SppA and TepA, with similarity to the signal peptide peptidase A of Escherichia coli. Notably, TepA also shows similarity to ClpP proteases. SppA of B. subtilis was only required for efficient processing of pre-proteins under conditions of hyper-secretion. In contrast, TepA depletion had a strong effect on pre-protein translocation across the membrane and subsequent processing, not only under conditions of hyper-secretion. Unlike SppA, which is a typical membrane protein, TepA appears to have a cytosolic localization, which is consistent with the observation that TepA is involved in early stages of the secretion process. Our observations demonstrate that SppA and TepA have a role in protein secretion in B. subtilis. Based on their similarity to known proteases, it seems likely that SppA and TepA are specifically required for the degradation of proteins or (signal) peptides that are inhibitory to protein translocation.

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How proteins cross the bacterial cytoplasmic membrane

Cited by 61 publications

References 175 publications

Determination of the Transmembrane Topology of Yeast Sec61p, an Essential Component of the Endoplasmic Reticulum Translocation Complex

Determination of the Transmembrane Topology of Yeast Sec61p, an Essential Component of the Endoplasmic Reticulum Translocation Complex

Coupled structure change of SecA and SecG revealed by the synthetic lethality of the secAcsR11 and ΔsecG::kan double mutant

Signal Peptide Peptidase- and ClpP-like Proteins of Bacillus subtilis Required for Efficient Translocation and Processing of Secretory Proteins

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