Interactions between flagellar and type III secretion proteins in Chlamydia pneumoniae
Authors: Raman K Toor
Jodi D Gilchrist
David C Bulir
James B Mahony
Chris B Stone
Journal: BMC Microbiology (2010)
Discipline: MICROBIOLOGY
Keywords: Flagellar secretion systems; bacteria; Chlamydia pneumoniae; FliI; FlhA
Affiliations: M,G, DeGroote Institute for Infectious Disease Research, Faculty of Health Sciences and the Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada.

Abstract:  Background: Flagellar secretion systems are utilized by a wide variety of bacteria to construct the flagellum, a conserved apparatus that allows for migration towards non-hostile, nutrient rich environments. Chlamydia pneumoniae is an obligate, intracellular pathogen whose genome contains at least three orthologs of flagellar proteins, namely FliI, FlhA and FliF, but the role of these proteins remains unknown. Results: Full length FliI, and fragments of FlhA, FliF, and FliI, were cloned and expressed as either GST or His tagged proteins in E. coli. The GST-tagged full length FliI protein was shown to possess ATPase activity, hydrolyzing ATP at a rate of 0.15 +/- .02 micromol min-1 mg-1 in a time- and dose-dependant manner. Using bacterial-2-hybrid and GST pull-down assays, the N-terminal domain of FliI was shown to interact with the cytoplasmic domain of FlhA, but not with FliF, and the cytoplasmic domain of FlhA was shown to interact with the C-terminus of FliF. The absence of other flagellar orthologs led us to explore cross-reaction of flagellar proteins with type III secretion proteins, and we found that FliI interacted with CdsL and CopN, while FlhA interacted with CdsL and Cpn0322 (YscU ortholog CdsU). Conclusions: The specific interaction of the four orthologous flagellar proteins in C. pneumoniae suggests that they interact in vivo and, taken together with their conservation across members of the chlamydiae sps., and their interaction with T3S components, suggests a role in bacterial replication and/or intracellular survival. 

Retracted: No

PubPeer comments:
 Figure 3. * Red boxes: Three blots without any signal appear to look more similar than expected. Reported to the journal in July 2015, but the issue has not yet been resolved. Could the authors please clarify if the journal ever contacted them in the past five+ years? ![file] , 
 Figure 4 raises a similar concern. * Blue boxes: Three blots appear to look more similar than expected. Contrast enhanced to bring out details. ![file] , 
 A similar concern was flagged by me on [another paper] which shares the same first and last author. It seems as if the first author may have left academia. In fact, the figure Dr. Bik posted here appears to be drawn from the [first authoru2019s PhD thesis] , which makes one wonder if these concerns were identified by others previously. *** ![file] *** ![file] ![file] , 
 Hello, yes the journal contacted me several years ago and I provided them with all the gels from the original work, which supported the results. Once I provided the information I never heard back from the journal so I assumed it was all normal from there? Hope this helps, , 
 ![file] ![file] ![file] Hope these are helpful- I will try and track down the rest of the figures to post here! ,