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A telomerase subunit homolog La protein from Trypanosoma brucei plays an essential role in ribosomal biogenesis
Author(s) -
Shan Fangzhen,
Mei Song,
Zhang Jiahai,
Zhang Xuecheng,
Xu Chao,
Liao Shanhui,
Tu Xiaoming
Publication year - 2019
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.14853
Subject(s) - ribosome biogenesis , ribosomal protein , biology , ribosome , ribosomal rna , eukaryotic large ribosomal subunit , rna polymerase i , eukaryotic small ribosomal subunit , trypanosoma brucei , protein subunit , 5s ribosomal rna , microbiology and biotechnology , rna , genetics , rna polymerase , gene
The autoantigen La protein is an important component of telomerase and a predominantly nuclear phosphoprotein. As a telomerase subunit, La protein associates with the telomerase ribonucleoprotein and influences telomere length. In the reverse transcription, La protein stimulates enzymatic activity and increases repeated addition processivity of telomerase. As nuclear phosphoprotein, La protein binds the 3′ poly(U)‐rich elements of nascent RNA polymerase III transcripts to facilitate its correct folding and maturation. In this work, we identified a La protein homolog (TbLa) from Trypanosoma brucei ( T. brucei ). We revealed that TbLa interacts with ribosome‐associated protein P34/P37, 40S ribosomal protein SA, and 60S ribosomal subunit L5 in T. brucei . In the interactions between TbLa protein and (P34/P37)/L5/SA, RNA recognition motif (RRM) domain of TbLa was indicated to make the major contribution to the processes. We determined the solution structure of TbLa RRM domain. NMR chemical shift perturbations revealed that the positively charged RNA‐binding pocket of TbLa RRM domain is responsible for its interaction with ribosomal and ribosome‐associated proteins P37/L5/SA. Furthermore, depletion of TbLa affected the maturation process of 5S rRNA and ribosomal assembly, suggesting TbLa protein might play a significant role in the ribosomal biogenesis pathway in T. brucei . Taken together, our results provide a novel insight and structural basis for better understanding the roles of TbLa and RRM domain in ribosomal biogenesis in T. brucei . Database Structural data are available in the PDB under the accession number 5ZUH .