title: Ubiquitination of mRNA cycling sequence binding protein from Leishmania donovani (LdCSBP) modulates the RNA endonuclease activity of its Smr domain.
abstract: In trypanosomatid parasites, an octanucleotide sequence (C/A)AUAGAA(G/A) in the UTRs primarily determines the stability of S-phase specific mRNAs. A multi-domain protein LdCSBP from Leishmania donovani interacts with the UTR of an S-phase RNA containing the octanucleotide sequence through its unique CCCH-type Zn-finger motifs. Interestingly, the RNA binding protein contains a previously characterized DNA endonuclease domain - Smr. It has been demonstrated here that the LdCSBP Smr domain independently possesses both DNA and RNA endonuclease activities, but the full-length LdCSBP exhibits only riboendonuclease activity. Moreover, LdCSBP protein has been shown to be ubiquitinated, resulting in the down-regulation of its riboendonuclease activity. In conclusion, the results described here suggest a novel regulatory mechanism of mRNA degradation through ubiquitination in eukaryotes.
authors.affiliation: Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Kolkata 700064, India.
authors.forename: Dipankar
authors.initials: D
authors.lastname: Bhandari
authors.forename: Kasturi
authors.initials: K
authors.lastname: Guha
authors.forename: Nipa
authors.initials: N
authors.lastname: Bhaduri
authors.forename: Partha
authors.initials: P
authors.lastname: Saha
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D016054:DNA, Protozoan / Q000378:metabolism; D004720:Endonucleases / Q000378:metabolism*; D007893:Leishmania donovani / Q000378:metabolism*; D008969:Molecular Sequence Data; D025821:Polyubiquitin / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry* / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D016053:RNA, Protozoan / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism; D016196:S Phase; D054875:Ubiquitination; D016335:Zinc Fingers
chemical_list: D020121:5' Untranslated Regions; D016054:DNA, Protozoan; D015800:Protozoan Proteins; D012333:RNA, Messenger; D016053:RNA, Protozoan; D025821:Polyubiquitin; D004720:Endonucleases; D012260:Ribonucleases