title: C-terminal domain of CagX is responsible for its interaction with CagT protein of Helicobacter pylori type IV secretion system.
abstract: Helicobacter pylori are the well known human pathogen associated with gastric cancer and peptic ulcer. Pathogenesis is mainly due to the presence of 40 kb cagPAI (cag Pathogenicity Island) region that encodes the type IV secretion system (TFSS) consisting of a cytoplasmic part, a middle part/core complex (spans from inner membrane to outer membrane), and an outer membrane associated part. CagX and CagT are two important proteins of TFSS that have homology with virB9 and virB7 of Agrobacterium tumefaciens TFSS. In this study, we have shown that the CagX and CagT interact directly by using co-immunoprecipitation of endogenous CagX and CagT and MBP pull down assay. We further authenticate this observation using yeast two-hybrid assay and co-expression of both the protein coding gene in Escherichia coli. We also observed that the C-terminal region of CagX is important for CagT interaction. We reconfirm that CagT depends on CagX for its stabilization. These observations could contribute in overall visualization of assembly and architecture of TFSS because protein-protein interactions among Cag proteins are likely to have an important role in assembly. Thorough understanding about architecture and mechanism of action of cag-TFSS may lead to design controlled drug delivery system.
authors.affiliation: Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India; Department of Biochemistry, M.S. University of Baroda, Vadodara, Gujarat, India. Electronic address: gopaljigopal@rediffmail.com.
authors.forename: Gopal Jee
authors.initials: GJ
authors.lastname: Gopal
authors.affiliation: Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India; Department of Medical Oncology, Dana Farber Cancer Institute, Boston, MA, USA.
authors.forename: Jagannath
authors.initials: J
authors.lastname: Pal
authors.affiliation: Department of Biotechnology, National Institute of Technology, Raipur, Chhattisgarh, India.
authors.forename: Awanish
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India. Electronic address: garunga@hotmail.com.
authors.forename: Gauranga
authors.initials: G
authors.lastname: Mukhopadhyay
mesh_terms: D000942:Antigens, Bacterial / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D058947:Bacterial Secretion Systems; D002352:Carrier Proteins / Q000378:metabolism*; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D016503:Drug Delivery Systems; D044404:Genomic Islands; D016480:Helicobacter pylori / Q000235:genetics / Q000378:metabolism*; D047468:Immunoprecipitation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; D002352:Carrier Proteins; D011994:Recombinant Proteins; D004247:DNA
keywords: CagT/CagX; H. pylori; Interaction; TFSS; Yeast-two-hybrid system