Plasmodium falciparum RUVBL3 protein: a novel DNA modifying enzyme and an interacting partner of essential HAT protein MYST.

RUVBLs constitute a conserved group of ATPase proteins that play significant role in a variety of cellular processes including transcriptional regulation, cell cycle and DNA damage repair. Three RUVBL homologues, namely, PfRUVBL1, PfRUVBL2 and PfRUVBL3 have been identified in P. falciparum, unlike its eukaryotic counterparts, which have two RUVBL proteins (RUVBL1 & RUVBL2). The present study expands our understanding of PfRUVBL3 protein and thereby basic biology of Plasmodium in general. Here, we have shown that parasite PfRUVBL3 is a true homolog of human/yeast RUVBL2 protein. Our result show that PfRUVBL3 constitutively expresses throughout the stages of intra-erythrocytic cycle (IDC) with varied localization. In addition to ATPase and oligomerization activity, we have for the first time shown that PfRUVBL3 possess DNA cleavage activity which interestingly is dependent on its insertion domain. Furthermore, we have also identified RUVBL3 to be an interacting partner of an essential chromatin remodeling protein PfMYST and together they colocalize with H3K9me1 histone in parasitophorous vacuole during the ring stage of IDC suggesting their potential involvement in chromatin remodeling and gene transcription.