Ribosomal P3 protein AtP3B of Arabidopsis acts as both protein and RNA chaperone to increase tolerance of heat and cold stresses.

The P3 proteins are plant-specific ribosomal P-proteins; however, their molecular functions have not been characterized. In a screen for components of heat-stable high-molecular weight (HMW) complexes, we isolated the P3 protein AtP3B from heat-treated Arabidopsis suspension cultures. By size-exclusion chromatography (SEC), SDS-PAGE and native PAGE followed by immunoblotting with anti-AtP3B antibody, we showed that AtP3B was stably retained in HMW complexes following heat shock. The level of AtP3B mRNA increased in response to both high- and low-temperature stresses. Bacterially expressed recombinant AtP3B protein exhibited both protein and RNA chaperone activities. Knockdown of AtP3B by RNAi made plants sensitive to both high- and low-temperature stresses, whereas overexpression of AtP3B increased tolerance of both conditions. Together, our results suggest that AtP3B protects cells against both high- and low-temperature stresses. These findings provide novel insight into the molecular functions and in vivo roles of acidic ribosomal P-proteins, thereby expanding our knowledge of the protein production machinery. © 2016 John Wiley & Sons Ltd.

Citation

Chang Ho Kang, Young Mee Lee, Joung Hun Park, Ganesh M Nawkar, Hun Taek Oh, Min Gab Kim, Soo In Lee, Woe Yeon Kim, Dae-Jin Yun, Sang Yeol Lee. Ribosomal P3 protein AtP3B of Arabidopsis acts as both protein and RNA chaperone to increase tolerance of heat and cold stresses. Plant, cell & environment. 2016 Jul;39(7):1631-42

PMID: 27004478

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