Processing of Chlamydia abortus polymorphic membrane protein 18D during the chlamydial developmental cycle

Nick M. Wheelhouse, Michelle Sait, Kevin Aitchison, Morag Livingstone, Frank Wright, Kevin McLean, Neil F. Inglis, David George Emslie Smith, David Longbottom

    Research output: Contribution to journalArticlepeer-review

    16 Citations (Scopus)


    BACKGROUND: Chlamydia possess a unique family of autotransporter proteins known as the Polymorphic membrane proteins (Pmps). While the total number of pmp genes varies between Chlamydia species, all encode a single pmpD gene. In both Chlamydia trachomatis (C. trachomatis) and C. pneumoniae, the PmpD protein is proteolytically cleaved on the cell surface. The current study was carried out to determine the cleavage patterns of the PmpD protein in the animal pathogen C. abortus (termed Pmp18D).

    METHODOLOGY/PRINCIPAL FINDINGS: Using antibodies directed against different regions of Pmp18D, proteomic techniques revealed that the mature protein was cleaved on the cell surface, resulting in a100 kDa N-terminal product and a 60 kDa carboxy-terminal protein. The N-terminal protein was further processed into 84, 76 and 73 kDa products. Clustering analysis resolved PmpD proteins into three distinct clades with C. abortus Pmp18D, being most similar to those originating from C. psittaci, C. felis and C. caviae.

    CONCLUSIONS/SIGNIFICANCE: This study indicates that C. abortus Pmp18D is proteolytically processed at the cell surface similar to the proteins of C. trachomatis and C. pneumoniae. However, patterns of cleavage are species-specific, with low sequence conservation of PmpD across the genus. The absence of conserved domains indicates that the function of the PmpD molecule in chlamydia remains to be elucidated.

    Original languageEnglish
    Article numbere49190
    JournalPLoS ONE
    Issue number11
    Publication statusPublished - 2012


    • Bacterial Proteins
    • Chlamydia Infections
    • Chlamydia trachomatis
    • Gene Expression Regulation, Bacterial
    • Humans
    • Membrane Proteins
    • Phylogeny
    • Proteomics
    • Sequence Homology, Amino Acid


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