Moraxella catarrhalis binding to host cellular receptors is mediated by sequence-specific determinants not conserved among all UspA1 protein variants

Michael J. Brooks, Jennifer L. Sedillo, Nikki Wagner, Wei Wang, Ahmed S. Attia, Henry Wong, Cassie A. Laurence, Eric J. Hansen, Scott D. Gray-Owen

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

The Moraxella catarrhalis ubiquitous surface proteins (UspAs) are autotransporter molecules reported to interact with a variety of different host proteins and to affect processes ranging from serum resistance to cellular adhesion. The role of UspA1 as an adhesin has been confirmed with a number of different human cell types and is mediated by binding to eukaryotic proteins including carcinoembryonic antigen-related cellular adhesion molecules (CEACAMs), fibronectin, and laminin. A distinct difference in the ability of prototypical M. catarrhalis strains to adhere to CEACAM-expressing cell lines prompted us to perform strain-specific structure-function analyses of UspA1 proteins. In this study, we characterized CEACAM binding by a diverse set of UspA1 proteins and showed that 3 out of 10 UspA1 proteins were incapable of binding CEACAM. This difference resulted from the absence of a distinct CEACAM binding motif in nonadhering strains. Our sequence analysis also revealed a single M. catarrhalis isolate that lacked the fibronectin-binding motif and was defective in adherence to Chang conjunctival epithelial cells. These results clearly demonstrate that UspA1-associated adhesive functions are not universally conserved. Instead, UspA1 proteins must be considered as variants with the potential to confer both different cell tropisms and host cell responses.

Original languageEnglish (US)
Pages (from-to)5322-5329
Number of pages8
JournalInfection and immunity
Volume76
Issue number11
DOIs
StatePublished - Nov 1 2008

ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases

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    Brooks, M. J., Sedillo, J. L., Wagner, N., Wang, W., Attia, A. S., Wong, H., Laurence, C. A., Hansen, E. J., & Gray-Owen, S. D. (2008). Moraxella catarrhalis binding to host cellular receptors is mediated by sequence-specific determinants not conserved among all UspA1 protein variants. Infection and immunity, 76(11), 5322-5329. https://doi.org/10.1128/IAI.00572-08