title: Interaction between FtsW and penicillin-binding protein 3 (PBP3) directs PBP3 to mid-cell, controls cell septation and mediates the formation of a trimeric complex involving FtsZ, FtsW and PBP3 in mycobacteria.
abstract: In bacteria, biogenesis of cell wall at the division site requires penicillin-binding protein 3 (PBP3) (or Ftsl). Using pull-down, bacterial two-hybrid, and peptide-based interaction assays, we provide evidence that FtsW of Mycobacterium tuberculosis (FtsWMTB) interacts with PBP3 through two extracytoplasmic loops. Pro306 in the larger loop and Pro386 in the smaller loop of FtsW are crucial for these interactions. Fluorescence microscopy shows that conditional silencing of ftsW in Mycobacterium smegmatis prevents cell septation and positioning of PBP3 at mid-cell. Pull-down assays and conditional depletion of FtsW in M. smegmatis provide evidence that FtsZ, FtsW and PBP3 of mycobacteria are capable of forming a ternary complex, with FtsW acting as a bridging molecule. Bacterial three-hybrid analysis suggests that in M. tuberculosis, the interaction (unique to mycobacteria) of FtsZ with the cytosolic C-tail of FtsW strengthens the interaction of FtsW with PBP3. ftsW of M. smegmatis could be replaced by ftsW of M. tuberculosis. FtsWMTB could support formation of the FtsZ-FtsW-PBP3 ternary complex in M. smegmatis. Our findings raise the possibility that in the genus Mycobacterium binding of FtsZ to the C-tail of FtsW may modulate its interactions with PBP3, thereby potentially regulating septal peptidoglycan biogenesis.
authors.affiliation: Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India.
authors.forename: Pratik
authors.initials: P
authors.lastname: Datta
authors.forename: Arunava
authors.initials: A
authors.lastname: Dasgupta
authors.forename: Anil Kumar
authors.initials: AK
authors.lastname: Singh
authors.forename: Partha
authors.initials: P
authors.lastname: Mukherjee
authors.forename: Manikuntala
authors.initials: M
authors.lastname: Kundu
authors.forename: Joyoti
authors.initials: J
authors.lastname: Basu
mesh_terms: D016375:Antisense Elements (Genetics) / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D047468:Immunoprecipitation; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009161:Mycobacterium / Q000235:genetics / Q000378:metabolism*; D046915:Penicillin-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011392:Proline / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D020798:Two-Hybrid System Techniques
chemical_list: D016375:Antisense Elements (Genetics); D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; C071525:FtsZ protein, Bacteria; D008565:Membrane Proteins; D046912:Multiprotein Complexes; D046915:Penicillin-Binding Proteins; C061684:FtsW protein, Bacteria; D011392:Proline