scholarly journals A working model for condensate RNA-binding proteins as matchmakers for protein complex assembly

RNA ◽  
2021 ◽  
pp. rna.078995.121
Author(s):  
Xiuzhen Chen ◽  
Christine Mayr
Keyword(s):  
Protein Complex ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protein Complexes ◽  
Complex Assembly ◽  
Protein Targets ◽  
Working Model ◽  
Cellular Environment ◽  
Protein Complex Assembly

Most cellular processes are carried out by protein complexes, but it is still largely unknown how the subunits of lowly expressed complexes find each other in the crowded cellular environment. Here, we will describe a working model where RNA-binding proteins in cytoplasmic condensates act as matchmakers between their bound proteins (called protein targets) and newly translated proteins of their RNA targets to promote their assembly into complexes. Different RNA-binding proteins act as scaffolds for various cytoplasmic condensates with several of them supporting translation. mRNAs and proteins are recruited into the cytoplasmic condensates through binding to specific domains in the RNA-binding proteins. Scaffold RNA-binding proteins have a high valency. In our model, they use homotypic interactions to assemble condensates and they use heterotypic interactions to recruit protein targets into the condensates. We propose that unoccupied binding sites in the scaffold RNA-binding proteins transiently retain recruited and newly translated proteins in the condensates, thus promoting their assembly into complexes. Taken together, we propose that lowly expressed subunits of protein complexes combine information in their mRNAs and proteins to colocalize in the cytoplasm. The efficiency of protein complex assembly is increased by transient entrapment accomplished by multivalent RNA-binding proteins within cytoplasmic condensates.

scholarly journals Multiple roles of heterogeneous nuclear ribonucleoprotein K during skeletal muscle cell differentiation

2021 ◽  
Author(s):  
Keisuke Hitachi ◽  
Yuri Kiyofuji ◽  
Masashi Nakatani ◽  
Kunihiro Tsuchida
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protein Complexes ◽  
Myogenic Differentiation ◽  
Cell Physiology ◽  
Transcriptional Level ◽  
Loss Of Function ◽  
Independent Manner ◽  
Multiple Functions

RNA-binding proteins (RBPs) regulate cell physiology via the formation of ribonucleic-protein complexes with coding and non-coding RNAs. RBPs have multiple functions in the same cells; however, the precise mechanism through which their pleiotropic functions are determined remains unknown. In this study, we revealed the multiple inhibitory functions of hnRNPK for myogenic differentiation. We first identified hnRNPK as a lncRNA Myoparr binding protein. Gain- and loss-of-function experiments showed that hnRNPK repressed the expression of myogenin at the transcriptional level via binding to Myoparr. Moreover, hnRNPK repressed the expression of a set of genes coding for aminoacyl-tRNA synthetases in a Myoparr-independent manner. Mechanistically, hnRNPK regulated the eIF2α/Atf4 pathway, one branch of the intrinsic pathways of the endoplasmic reticulum sensors, in differentiating myoblasts. Thus, our findings demonstrate that hnRNPK plays multiple lncRNA-dependent and -independent roles in the inhibition of myogenic differentiation, indicating that the analysis of lncRNA-binding proteins will be useful for elucidating both the physiological functions of lncRNAs and the multiple functions of RBPs.

The 5S RNA – protein complex from yeast: a model for the evolution and structure of the eukaryotic ribosome

1982 ◽  
Vol 60 (4) ◽  
pp. 490-496 ◽  
Author(s):  
Ross N. Nazar ◽  
Makoto Yaguchi ◽  
Gordon E. Willick
Keyword(s):  
Binding Site ◽  
Protein Complex ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protein Complexes ◽  
Basic Structure ◽  
5S Rna ◽  
Chemical Studies ◽  
Physical And Chemical ◽  
Rna Protein Complexes

The ribosomal 5S RNA – protein complex appears to be an excellent model for studies on the evolution and structure of ribosomes. In eukaryotes this complex is composed of two components, the 5S rRNA and a single ribosomal protein which in yeast has a molecular weight of about 38 000. The primary protein-binding site is located in the 3′-end region of the 5S RNA together with a small portion of the 5′ end. The primary RNA-binding site appears to be situated in the C-terminal end of the protein (YL3 in yeast) but the binding specificity requires other structural elements in the N-terminal half of the molecule. When compared with prokaryotic 5S RNA – protein complexes, various physical and chemical studies suggest that the basic structure and interactions have been conserved in the course of evolution, but that the single larger eukaryotic 5S RNA binding protein has evolved through a fusion of genes for the multiple 5S RNA binding proteins in prokaryotes.

Regulation of the ELAV target ewg: insights from an evolutionary perspective

2008 ◽  
Vol 36 (3) ◽  
pp. 502-504 ◽  
Author(s):  
Matthias Soller ◽  
Min Li ◽  
Irmgard U. Haussmann
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Mrna Processing ◽  
Untranslated Regions ◽  
Cellular Environment ◽  
Specific Regulation ◽  
Abnormal Visual ◽  
Recent Sequencing

ELAV (embryonic lethal abnormal visual system)/Hu family proteins are prototype RNA-binding proteins with binding preferences for AU-rich regions. Due to frequent occurrence of AU-rich motifs in introns and untranslated regions, it is poorly understood how gene-specific RNA-binding proteins, such as ELAV/Hu family members, recognize their complement of target RNAs in a complex cellular environment. The powerful genetic tools of Drosophila make the fruitfly an excellent model to study alternative mRNA processing in vivo in a developing organism. Recent sequencing of 12 Drosophila genomes will provide a novel resource to enhance our understanding of how gene-specific regulation of mRNA processing is achieved by ELAV/Hu family proteins.

scholarly journals RBP2GO: a comprehensive pan-species database on RNA-binding proteins, their interactions and functions

2020 ◽  
Vol 49 (D1) ◽  
pp. D425-D436 ◽  
Author(s):  
Maiwen Caudron-Herger ◽  
Ralf E Jansen ◽  
Elsa Wassmer ◽  
Sven Diederichs
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protein Complexes ◽  
Rapid Evolution ◽  
Cellular Processes ◽  
Advanced Search ◽  
New Research ◽  
Cellular Compartments ◽  
User Friendly

Abstract RNA–protein complexes have emerged as central players in numerous key cellular processes with significant relevance in health and disease. To further deepen our knowledge of RNA-binding proteins (RBPs), multiple proteome-wide strategies have been developed to identify RBPs in different species leading to a large number of studies contributing experimentally identified as well as predicted RBP candidate catalogs. However, the rapid evolution of the field led to an accumulation of isolated datasets, hampering the access and comparison of their valuable content. Moreover, tools to link RBPs to cellular pathways and functions were lacking. Here, to facilitate the efficient screening of the RBP resources, we provide RBP2GO (https://RBP2GO.DKFZ.de), a comprehensive database of all currently available proteome-wide datasets for RBPs across 13 species from 53 studies including 105 datasets identifying altogether 22 552 RBP candidates. These are combined with the information on RBP interaction partners and on the related biological processes, molecular functions and cellular compartments. RBP2GO offers a user-friendly web interface with an RBP scoring system and powerful advanced search tools allowing forward and reverse searches connecting functions and RBPs to stimulate new research directions.

scholarly journals Co-translational assembly of protein complexes

2015 ◽  
Vol 43 (6) ◽  
pp. 1221-1226 ◽  
Author(s):  
Jonathan N. Wells ◽  
L. Therese Bergendahl ◽  
Joseph A. Marsh
Keyword(s):  
Protein Complex ◽  
Protein Complexes ◽  
Biological Macromolecules ◽  
Complex Assembly ◽  
Cellular Life ◽  
Eukaryotic Organisms ◽  
Protein Complex Assembly

The interaction of biological macromolecules is a fundamental attribute of cellular life. Proteins, in particular, often form stable complexes with one another. Although the importance of protein complexes is widely recognized, we still have only a very limited understanding of the mechanisms underlying their assembly within cells. In this article, we review the available evidence for one such mechanism, namely the coupling of protein complex assembly to translation at the polysome. We discuss research showing that co-translational assembly can occur in both prokaryotic and eukaryotic organisms and can have important implications for the correct functioning of the complexes that result. Co-translational assembly can occur for both homomeric and heteromeric protein complexes and for both proteins that are translated directly into the cytoplasm and those that are translated into or across membranes. Finally, we discuss the properties of proteins that are most likely to be associated with co-translational assembly.

scholarly journals The role of disorder in RNA binding affinity and specificity

Open Biology ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 200328
Author(s):  
Diana S. M. Ottoz ◽  
Luke E. Berchowitz
Keyword(s):  
Protein Interactions ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Multiple Partners ◽  
Cellular Environment ◽  
Rna Targets

Most RNA-binding modules are small and bind few nucleotides. RNA-binding proteins typically attain the physiological specificity and affinity for their RNA targets by combining several RNA-binding modules. Here, we review how disordered linkers connecting RNA-binding modules govern the specificity and affinity of RNA–protein interactions by regulating the effective concentration of these modules and their relative orientation. RNA-binding proteins also often contain extended intrinsically disordered regions that mediate protein–protein and RNA–protein interactions with multiple partners. We discuss how these regions can connect proteins and RNA resulting in heterogeneous higher-order assemblies such as membrane-less compartments and amyloid-like structures that have the characteristics of multi-modular entities. The assembled state generates additional RNA-binding specificity and affinity properties that contribute to further the function of RNA-binding proteins within the cellular environment.

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