Dual protection by Bcp1 and Rkm1 ensures incorporation of uL14 into pre-60S ribosomal subunits
Journal
Journal of Cell Biology
Journal Volume
223
Journal Issue
8
ISSN
0021-9525
1540-8140
Date Issued
2024-07-15
Author(s)
Min-Chi Yeh
Ning-Hsiang Hsu
Hao-Yu Chu
Cheng-Han Yang
Pang-Hung Hsu
Chi-Chi Chou
Jing-Ting Shie
Wei-Ming Lee
Meng-Chiao Ho
Abstract
Eukaryotic ribosomal proteins contain extended regions essential for translation coordination. Dedicated chaperones stabilize the associated ribosomal proteins. We identified Bcp1 as the chaperone of uL14 in Saccharomyces cerevisiae. Rkm1, the lysine methyltransferase of uL14, forms a ternary complex with Bcp1 and uL14 to protect uL14. Rkm1 is transported with uL14 by importins to the nucleus, and Bcp1 disassembles Rkm1 and importin from uL14 simultaneously in a RanGTP-independent manner. Molecular docking, guided by crosslinking mass spectrometry and validated by a low-resolution cryo-EM map, reveals the correlation between Bcp1, Rkm1, and uL14, demonstrating the protection model. In addition, the ternary complex also serves as a surveillance point, whereas incorrect uL14 is retained on Rkm1 and prevented from loading to the pre-60S ribosomal subunits. This study reveals the molecular mechanism of how uL14 is protected and quality checked by serial steps to ensure its safe delivery from the cytoplasm until its incorporation into the 60S ribosomal subunit.
SDGs
Publisher
Rockefeller University Press
Type
journal article