Genes encoding high-molecular-weight adhesion proteins of nontypeable Haemophilus influenzae are part of gene clusters

Barenkamp, Stephen J.; Geme, Joseph W. St.

doi:10.1128/iai.62.8.3320-3328.1994

Cited by 88 publications

(55 citation statements)

References 25 publications

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“…The 1B and 2B genes are 1.635 kb long and encode proteins that are 99% identical, while the 1C and 2C genes are 1.95 kb long and code for polypeptides that are 96% identical. In a recent study, we reported that, in experiments with Escherichia coli harbouring the hmw1 locus, deletion of part of hmw1C or all of hmw1C plus part of hmw1B resulted in defective processing and a loss of bacterial adherence (Barenkamp and St Geme, 1994).…”

Section: Introductionmentioning

confidence: 99%

Secretion of the Haemophilus influenzae HMW1 and HMW2 adhesins involves a periplasmic intermediate and requires the HMWB and HMWC proteins

Geme

Grass

1998

Molecular Microbiology

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Non-typable Haemophilus influenzae is a common cause of human disease and initiates infection by colonizing the upper respiratory tract. The non-typeable H. influenzae HMW1 and HMW2 non-pilus adhesins mediate attachment to human epithelial cells, an essential step during colonization. In order to facilitate interaction with host cells, HMW1 and HMW2 are localized on the surface of the organism in a process that involves cleavage of a 441-amino-acid N-terminal fragment. In the present study, we investigated the pathway for the secretion of HMW1 and HMW2. Cell fractionation experiments and cryoimmunoelectron microscopy demonstrated that a periplasmic intermediate occurs, suggesting involvement of the Sec machinery. Additional analysis revealed that, ultimately, the proteins are partially released from the surface of the organism. Studies with Escherichia coli harbouring plasmid subclones extended earlier findings and suggested that the secretion of HMW1 requires accessory proteins designated HMW1B and HMW1C, while the secretion of HMW2 requires proteins called HMW2B and HMW2C. Further analysis established that HMW1B/HMW1C and HMW2B/HMW2C are interchangeable, an observation consistent with the high degree of homology between HMW1B and HMW2B and between HMW1C and HMW2C. Additional studies of the hmw1 locus indicated that HMW1B is located in the outer membrane and serves to translocate HMW1 across the outer membrane. In the absence of HMW1B, HMW1 remains unprocessed and is degraded in the periplasmic space, at least in part by the DegP protease. Mutagenesis of an HMW1 N-terminal motif shared with other secreted proteins resulted in diminished processing and extracellular release, suggesting interaction of this motif with the HMW1B protein. Continued investigation of the HMW1 and HMW2 adhesins may provide general insights into protein secretion and bacterial pathogenesis.

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Section: Introductionmentioning

confidence: 99%

Secretion of the Haemophilus influenzae HMW1 and HMW2 adhesins involves a periplasmic intermediate and requires the HMWB and HMWC proteins

Geme

Grass

1998

Molecular Microbiology

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“…S1A). The other three YtpsA proteins harbor an N-terminal extension in their SP, as also seen in FHA (Delisse-Gathoye et al, 1990), HMW1A (Barenkamp & St Geme, 1994), and LspA1 (Ward et al, 1998). Residues in this extension appear to be more conserved than those in the subsequent regions of the SP.…”

Section: Further Analyses Of the Tps Systems In Y Pestis Kimmentioning

confidence: 87%

Genome-widein silicomapping of the secretome in pathogenicYersinia pestisKIM

Yen

Bhattacharya

Stathopoulos

2008

FEMS Microbiology Letters

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Uncovering the secretome of Yersinia pestis is a necessary measure to better understand the virulence of this plague-causing bacterium. Using bioinformatics methods, the components of all the secretion systems known to date in the Y. pestis KIM genome were mapped, including several systems identified by this study. It was found that this organism possesses Sec, twin-arginine translocation, signal recognition particle, Omp85/YaeT, type I, type II, type III, type VI, chaperone/usher, autotransporter, and two-partner secretion (TPS) systems, but lacks a type IV secretion system. The TPS systems caught the authors' attention, for they are used by several bacterial pathogens for the secretion of large virulence determinants. Reverse transcriptase-PCR analysis confirmed the gene expression of three TPS systems in Y. pestis KIM; bioinformatics studies indicated that the exoproteins of these TPS systems are putative hemolysins and adhesins. Results thus suggest that these are functional systems, capable of secreting virulence proteins that might contribute to plague infection. This is the first report on the complete secretome of pathogenic Y. pestis KIM.

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“…Whole-cell sonicates were prepared by resuspending bacterial pellets in 10 mM HEPES, pH 7.4 and sonicating to clarity. Proteins released from the surface of the organism were recovered by precipitating culture supernatants with 10% trichloroacetic acid (TCA) as described previously (Barenkamp and St. Geme, 1994). Total membranes were recovered by centrifugation of cleared bacterial sonicates.…”

Section: Methodsmentioning

confidence: 99%

“…HMW1 and HMW2 are expressed by~80% of non-typeable H. influenzae clinical isolates and are encoded by separate chromosomal loci, each consisting of three genes, designated hmwA, hmwB and hmwC (Barenkamp and St. Geme, 1994;Buscher et al, 2004). The hmwA gene encodes the adhesin (the TpsA protein), the hmwB gene encodes the outer-membrane translocator protein (the TpsB protein), and the hmwC gene encodes a protein with possible glycosyltransferase activity (Barenkamp and St. Geme, 1994;St. Geme and Grass, 1998;Grass et al, 2003;Surana et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Surface anchoring of a bacterial adhesin secreted by the two‐partner secretion pathway

Buscher

Grass

Heuser

et al. 2006

Molecular Microbiology

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In Gram-negative bacteria, most surface-associated proteins are present as integral outer-membrane proteins. Exceptions include the Haemophilus influenzae HMW1 and HMW2 adhesins and a subset of other proteins secreted by the two-partner secretion system. In the present study we sought to determine the mechanism by which HMW1 is anchored to the bacterial surface. In initial experiments we found that HMW1 forms hair-like fibres on the bacterial surface and is usually present as pairs that appear to be joined together at one end. Further analysis established that HMW1 is anchored to the multimeric HMW1B outer membrane translocator, resulting in a direct correlation between the level of surface-associated HMW1 and the quantity of HMW1B in the outer membrane. Mutagenesis and polyethylene glycol maleimide labelling revealed that anchoring of HMW1 requires the C-terminal 20 amino acids of the protein and is dependent upon disulphide bond formation between two conserved cysteine residues in this region. Immunolabelling studies demonstrated that the immediate C-terminus of HMW1 is inaccessible to surface labelling, suggesting that it remains in the periplasm or is buried in HMW1B. Coexpression of HMW1 lacking the C-terminal 20 amino acids and wild-type HMW1 supported the conclusion that the C-terminus of HMW1 occupies the HMW1B pore. These observations may have broad relevance to proteins secreted by the two-partner secretion system, especially given the conservation of C-terminal cysteine residues among surface-associated proteins in this family.

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Genes encoding high-molecular-weight adhesion proteins of nontypeable Haemophilus influenzae are part of gene clusters

Cited by 88 publications

References 25 publications

Secretion of the Haemophilus influenzae HMW1 and HMW2 adhesins involves a periplasmic intermediate and requires the HMWB and HMWC proteins

Secretion of the Haemophilus influenzae HMW1 and HMW2 adhesins involves a periplasmic intermediate and requires the HMWB and HMWC proteins

Genome-widein silicomapping of the secretome in pathogenicYersinia pestisKIM

Surface anchoring of a bacterial adhesin secreted by the two‐partner secretion pathway

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