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Title: REACHING DESTINATIONS: SECRETED PROTEINS AND PROTEIN TRANSLOCATION PATHWAYS IN SPIROPLASMA KUNKELII

Author
item Zhao, Yan
item LIU, Q - TAIAN CHINA
item JOMANTIENE, R - VILNIUS LITHUANIA
item Hammond, Rosemarie
item Davis, Robert

Submitted to: American Phytopathological Society
Publication Type: Abstract Only
Publication Acceptance Date: 5/5/2004
Publication Date: 6/1/2004
Citation: Zhao, Y., Liu, Q., Jomantiene, R., Hammond, R., Davis, R.E. 2004. Reaching destinations: secreted proteins and protein translocation pathways in spiroplasma kunkelii. American Phytopathological Society. 94(s):116.

Interpretive Summary:

Technical Abstract: Spiroplasmas are cell wall-less, helical, and motile bacteria that parasitize insects, ticks, and plants. Under experimental conditions, certain spiroplasmas induce pathology in vertebrate animals. Spiroplasmas are thought to have evolved retrogressively from low G+C gram-positive bacteria and therefore to possess a compact genome with a gene set approaching the minimal complement necessary for cellular life and pathogenesis. The present study focused on the secreted and membrane-localized proteins and protein translocation systems encoded on the genome of Spiroplasma kunkelii, the causative agent of corn stunt disease and the first discovered spiroplasma. A total of 258 predicted proteins contained N-terminal signal peptides and/or membrane sorting signals. Genes encoding these proteins occupy 18% of the coding capacity of the entire genome. Based on the presence of genes encoding components of protein transport machineries and/or of signature motifs embedded in the signal peptides of transported preproteins, we predict the existence in S. kunkelii of multiple protein translocation pathways. These include a Sec-dependent secretion pathway, a type IV secretion pathway, a twin arginine pathway, a signal recognition particle-dependent pathway, and an ABC transporter-mediated pathway. Since protein translocation is a major determinant in microbial biology, including virulence, the discoveries from this study open new opportunities for understanding spiroplasma biology and pathogenesis.