A genome-wide analysis of annexins from parasitic organisms and their vectors

Cinzia Cantacessi, Jennifer M. Seddon, Terrence L. Miller, Chiuan Yee Leow, Laëtitia Thomas, Lyndel Mason, Charlene Willis, Giselle Walker, Alex Loukas, Robin B. Gasser, Malcolm K. Jones, Andreas Hofmann

In this study, we conduct an in-depth analysis of annexin proteins from a diverse range of invertebrate taxa, including the major groups that contain the parasites and vector organisms that are harmful to humans and domestic animals. Using structure-based amino acid sequence alignments and phylogenetic analyses, we present a classification for this protein group and assign names to sequences with ambiguous annotations in public databases. Our analyses reveal six distinct annexin clades, and the mapping of genes encoding annexins to the genome of the human blood fluke Schistosoma mansoni supports the hypothesis of gene duplication as a major evolutionary event in annexin genesis. This study illuminates annexin diversity from a novel perspective using contemporary phylogenetic hypotheses of eukaryote evolution, and will aid the consolidation of annexin protein identities in public databases and provide a foundation for future functional analysis and characterisation of these proteins in parasites of socioeconomic importance.