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Forward Genetic Approaches in Chlamydia trachomatis
Published on: October 23, 2013
CT295 Is Chlamydia trachomatis' Phosphoglucomutase and a Type 3 Secretion Substrate
Sébastien Triboulet1, Maimouna D N'Gadjaga1,2, Béatrice Niragire1
1Institut Pasteur, Université Paris Cité, CNRS UMR3691, Unité de Biologie Cellulaire de l'Infection Microbienne, Paris, France.
Chlamydia trachomatis bacteria convert stored glycogen into usable glucose-6-phosphate via a bacterial phosphoglucomutase (PGM). This process, facilitated by a type three secretion (T3S) signal, shapes glycogen metabolism in Chlamydiaceae.
Area of Science:
- Microbiology
- Bacterial Metabolism
- Molecular Biology
Background:
- Obligate intracellular bacteria *Chlamydia trachomatis* store glycogen within host-derived vacuoles.
- Glycogen breakdown yields glucose-1-phosphate (Glc1P), but *Chlamydia* can only import glucose-6-phosphate (Glc6P).
Purpose of the Study:
- To investigate the enzymatic conversion of Glc1P to Glc6P within *Chlamydia*-infected vacuoles.
- To identify the phosphoglucomutase (PGM) responsible for this conversion and explore its origin (host vs. bacterial).
Main Methods:
- Biochemical assays using purified proteins to test for PGM activity.
- Complementation studies using PGM-deficient fibroblasts.
- Bioinformatic analysis of *Chlamydia* CT295 orthologs for secretion signals.
Main Results:
- Host PGM was not detected within the vacuole.
- Bacterial protein CT295, but not CT815, demonstrated robust PGM activity.
- Glycogen accumulation in *Chlamydia* species correlated with the presence of a type three secretion (T3S) signal in CT295 orthologs.
Conclusions:
- Bacterial PGM (CT295) catalyzes the essential conversion of Glc1P to Glc6P.
- Acquisition of a T3S signal by CT295 likely influenced the evolution of glycogen metabolism in *Chlamydiaceae*.
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