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

Abstract

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.

Overexpression of Arabidopsis P3B increases heat and low temperature stress tolerance in transgenic sweetpotato

“…AtP3B -overexpressing transgenic Arabidopsis plants showed enhanced tolerance to heat and low temperature stress, whereas knockdown of AtP3B by RNAi led to increased sensitivity to both stresses [ 36 ]. In the current study, we evaluated the physiological functions of AtP3B using transgenic sweetpotato plants.…”

“…AtP3B plays an essential role in cold stress tolerance in Arabidopsis , a process mediated by its RNA chaperone activity [ 36 ]. Therefore, we investigated whether the OP plants also exhibited increased tolerance to low temperatures due to AtP3B overexpression.…”

“…AtP3B , which was originally isolated from heat-treated Arabidopsis suspension culture cells, plays essential roles in both heat and cold tolerance. AtP3B plays dual roles as a protein chaperone and an RNA chaperone; it prevents protein aggregation under heat stress, whereas it supports RNA processing or stability under cold stress [ 36 ]. In this study, ectopic expression of AtP3B in sweetpotato resulted in enhanced tolerance to heat and low temperature stress.…”

“…Recently, Kang et al identified a plant-specific acidic ribosomal P3 protein (designated AtP3B) as a heat-shock protein from heat-treated Arabidopsis suspension cells [ 36 ]. The authors demonstrated that AtP3B has both protein and RNA chaperone activities.…”

iTRAQ-based quantitative proteomics analysis of cantaloupe (Cucumis melo var. saccharinus) after cold storage

“…The functional analysis of DEPs in cantaloupe revealed that proteins involved in ribosomes and protein processing in the endoplasmic reticulum were highly enriched in both cultivars under cold treatment. Numerous studies have indicated that ribosomal proteins [39], endoplasmic reticulum related proteins [40] and molecular chaperones involved in protein folding [41] are essential for protein synthesis, and they have been speculated to play central roles in regulating stress tolerance in plants. In this study, 38 ribosome-related proteins were found in GE after 12 days of cold treatment, of which 21 were down-regulated and three (XP_008447825.1, XP_008447383.1, XP_008453374.1) were up-regulated.…”