Characterization of the Trypanosoma cruzi ortholog of the SBDS protein reveals an intrinsically disordered extended C-terminal region showing RNA-interacting activity.
The human SBDS gene and its yeast ortholog SDO1 encode essential proteins that are involved in ribosome biosynthesis. SDO1 has been implicated in recycling of the ribosomal biogenesis factor Tif6p from pre-66S particles as well as in translation activation of 60S ribosomes. The SBDS protein is highly conserved, containing approximately 250 amino acid residues in animals, fungi and Archaea, while SBDS orthologs of plants and a group of protists contain an extended C-terminal region. In this work, we describe the characterization of the Trypanosoma cruzi SBDS ortholog (TcSBDS). TcSBDS co-fractionates with polysomes in sucrose density gradients, which is consistent with a role in ribosome biosynthesis. We show that TcSBDS contains a C-terminal extension of 200 amino acids that displays the features of intrinsically disordered proteins as determined by proteolytic, circular dichroism and NMR analyses. Interestingly, the C-terminal extension is responsible for TcSBDS-RNA interaction activity in electrophoretic mobility shift assays. This finding suggests that Trypanosomatidae and possibly also other organisms containing SBDS with extended C-terminal regions have evolved an additional function for SBDS in ribosome biogenesis.
de Oliveira
Juliana Ferreira
JF
Center for Structural Molecular Biology, Brazilian Synchrotron Light Laboratory, LNLS, Rua Giuseppe Maximo Scolfaro 10000, PO Box 6192, CEP13083-970, Campinas SP, Brazil.
Castilho
Beatriz A
BA
Sforça
Mauricio L
ML
Krieger
Marco Aurélio
MA
Zeri
Ana Carolina
AC
Guimarães
Beatriz G
BG
Zanchin
Nilson I T
NI
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D008969:Molecular Sequence Data; D011132:Polyribosomes / Q000502:physiology; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012313:RNA / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012270:Ribosomes / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014349:Trypanosoma cruzi / Q000378:metabolism*
D011506:Proteins; D015800:Protozoan Proteins; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; C470521:SBDS protein, human; D029701:Saccharomyces cerevisiae Proteins; C520002:Sdo1 protein, S cerevisiae; D012313:RNA