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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
Author(s) -
Datta Pratik,
Dasgupta Arunava,
Singh Anil Kumar,
Mukherjee Partha,
Kundu Manikuntala,
Basu Joyoti
Publication year - 2006
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2006.05491.x
Subject(s) - ftsz , penicillin binding proteins , mycobacterium smegmatis , biology , microbiology and biotechnology , cell division , biochemistry , mycobacterium tuberculosis , cell , gene , escherichia coli , tuberculosis , medicine , pathology
Summary In bacteria, biogenesis of cell wall at the division site requires penicillin‐binding protein 3 (PBP3) (or FtsI). Using pull‐down, bacterial two‐hybrid, and peptide‐based interaction assays, we provide evidence that FtsW of Mycobacterium tuberculosis (FtsW MTB ) interacts with PBP3 through two extracytoplasmic loops. Pro 306 in the larger loop and Pro 386 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 . FtsW MTB 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.