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Updated: Aug 9, 2026
Polysome Fractionation and Analysis of Mammalian Translatomes on a Genome-wide Scale
Published on: May 17, 2014
Translational regulation by Y-box transcription factor: involvement of the major mRNA-associated protein, p50
V M Evdokimova1, L P Ovchinnikov
1Institute of Protein Research, Russian Academy of Sciences, Moscow Region, Russia.
Abstract:
p50, the major core protein of messenger ribonucleoprotein particles (mRNPs), is a universal protein found exclusively in association with different mRNA species in the cytoplasm of somatic mammalian cells. Furthermore, p50 is the most abundant and tightly bound protein within both inactive mRNPs and active mRNPs derived from polysomes, although the latter contain a lower level of p50. Recent experiments have revealed that, depending on the p50 to mRNA ratio, p50 may either act as a repressor or an activator of protein synthesis. On the other hand, p50 exhibits about 98% amino acid sequence identity to mammalian transcription factors that bind specifically to Y-box containing DNA. Thus, it is a counterpart of the Y-box binding proteins which are found in bacteria, plants and animals, exhibiting multiple biological activities ranging from transcriptional regulation of a wide variety of genes to 'masking' mRNA activity in germinal cells. This review summarizes our current knowledge of p50 structure and function. It also discusses the biological roles of p50 and related proteins in gene expression and describes the likely mechanisms of their action.
Insights
The p50 protein, a key component of messenger ribonucleoprotein particles (mRNPs), regulates protein synthesis by acting as either a repressor or activator. It also shares similarities with Y-box binding proteins involved in gene expression.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- p50 is the primary core protein of messenger ribonucleoprotein particles (mRNPs) in mammalian cells.
- It is abundant in both inactive and active mRNPs, with higher concentrations in inactive forms.
- p50 exhibits significant sequence identity to Y-box binding proteins.
Purpose of the Study:
- To review current knowledge on p50 protein structure and function.
- To discuss the biological roles of p50 and related proteins in gene expression.
- To explore the mechanisms of action for p50 and its counterparts.
Main Methods:
- Literature review of existing experimental data on p50.
- Comparative analysis of p50 with Y-box binding proteins.
- Synthesis of information on p50's role in protein synthesis and gene regulation.
Main Results:
- p50's function as a repressor or activator of protein synthesis is dependent on its ratio to mRNA.
- p50 is evolutionarily conserved, with counterparts in bacteria, plants, and animals.
- Y-box binding proteins regulate diverse genes and can 'mask' mRNA activity.
Conclusions:
- p50 plays a dual role in regulating protein synthesis.
- p50 and related Y-box binding proteins are crucial for diverse gene expression processes.
- Further research into p50's mechanisms can elucidate broader gene regulation pathways.
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