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DivIVA Phosphorylation Affects Its Dynamics and Cell Cycle in Radioresistant Deinococcus radiodurans
Reema Chaudhary1,2, Swathi Kota1,2, Hari S Misra1,2,3
1Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India.
Microbiology Spectrum
|February 6, 2023
Summary
The kinase RqkA phosphorylates DivIVA at threonine 19 in Deinococcus radiodurans, impacting its function and potentially causing cell cycle arrest after radiation exposure.
Area of Science:
- Microbiology
- Cell Biology
- Biochemistry
Background:
- Deinococcus radiodurans exhibits extreme resistance to DNA-damaging agents like radiation.
- Cell division regulation in D. radiodurans under DNA damage is not fully understood.
- DivIVA is a key protein regulating cell division and polarity in bacteria.
Purpose of the Study:
- To investigate the role of RqkA, a radiation-responsive kinase, in DivIVA regulation in D. radiodurans.
- To determine the functional consequences of DivIVA phosphorylation by RqkA.
- To elucidate mechanisms of cell cycle arrest in D. radiodurans following radiation.
Main Methods:
- Site-directed mutagenesis to create phospho-mimetic (T19E) and phospho-ablative (T19A) DivIVA mutants.
- Expression of DivIVA-RFP fusion proteins to study protein dynamics and interactions.
- Allelic replacement assays to assess the essentiality and function of modified DivIVA alleles.
Main Results:
- RqkA phosphorylates drDivIVA at threonine 19 (T19).
- The DivIVAT19E mutant showed altered dynamics, lost interaction with ParA2, and affected cell division.
- Phosphorylation of drDivIVA by RqkA attenuates its function and may contribute to radiation-induced cell cycle arrest.
Conclusions:
- RqkA-mediated phosphorylation of drDivIVA at T19 is crucial for its function in D. radiodurans.
- This phosphorylation event affects DivIVA's interaction with genome segregation proteins and its cellular dynamics.
- The findings provide insights into the DNA damage response and cell cycle regulation mechanisms in radioresistant bacteria.
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