The N-terminus region of Drp1, a Rint1 family protein is essential for cell survival and its interaction with Rad50 protein in fission yeast S.pombe.

Abstract Background Defects in DNA repair pathway can lead to double-strand breaks leading to genomic instability. Earlier we have shown that S.pombe Drp1, a Rint1/Tip1 family protein is required for the recovery from DNA damage. Methods Various truncations of Drp1 protein were constructed and their role in DNA damage response and interaction with Rad50 protein has been studied by co-immunoprecipitation and pull-down assays. Results The structural and functional analysis of Drp1 protein revealed that the N-terminus region of Drp1 is indispensable for the survival. The C-terminus truncation mutants, drp1C1Δ and drp1C2Δ exhibit temperature sensitive phenotype and are hypersensitive against DNA damaging agents with elevated level of Rad52-YFP foci at non-permissive temperature indicating the impairment for DNA damage repair pathway. The essential N-terminus region of Drp1 interacts with the C-terminus region of Rad50 and might be involved in influencing the MRN/X function. Small-angle X-ray (SAXS) analysis revealed three-domain like shapes in Drp1 protein while the C-terminus region of Rad50 exhibit unusual bulges. Computational docking studies revealed the amino acid residues at the C-terminus region of Rad50 that are involved in the interaction with the residues present at the N-terminal region of Drp1 indicating the importance of the N-terminal region of Drp1 protein. Conclusions We have identified the region of Drp1 and Rad50 proteins that are involved in the interaction and their role in the DNA damage response pathway has been analyzed. General significance The functional and structural aspects of fission yeast Drp1 protein and its interaction with Rad50 have been elucidated.