Towards understanding the catalytic core structure of the spliceosome

2005 ◽  
Vol 33 (3) ◽  
pp. 447-449 ◽  
Author(s):  
S.E. Butcher ◽  
D.A. Brow
Keyword(s):  
Structure And Function ◽  
Mrna Splicing ◽  
Catalytic Core ◽  
Coding Regions ◽  
High Resolution Structure ◽  
Associated Proteins ◽  
And Function ◽  
Mrna Precursor ◽  
Precursor Mrna ◽  
Resolution Structure

The spliceosome catalyses the splicing of nuclear pre-mRNA (precursor mRNA) in eukaryotes. Pre-mRNA splicing is essential to remove internal non-coding regions of pre-mRNA (introns) and to join the remaining segments (exons) into mRNA before translation. The spliceosome is a complex assembly of five RNAs (U1, U2, U4, U5 and U6) and many dozens of associated proteins. Although a high-resolution structure of the spliceosome is not yet available, inroads have been made towards understanding its structure and function. There is growing evidence suggesting that U2 and U6 RNAs, of the five, may contribute to the catalysis of pre-mRNA splicing. In this review, recent progress towards understanding the structure and function of U2 and U6 RNAs is summarized.

The ryanodine receptor provides high throughput Ca2+-release but is precisely regulated by networks of associated proteins: a focus on proteins relevant to phosphorylation

2015 ◽  
Vol 43 (3) ◽  
pp. 426-433 ◽  
Author(s):  
Fiona O'Brien ◽  
Elisa Venturi ◽  
Rebecca Sitsapesan
Keyword(s):  
Spatial Organization ◽  
Ryanodine Receptors ◽  
Integrated System ◽  
Fine Tuning ◽  
Control Mechanisms ◽  
Fk 506 ◽  
High Resolution Structure ◽  
Associated Proteins ◽  
And Function ◽  
Resolution Structure

Once opened, ryanodine receptors (RyR) are efficient pathways for the release of Ca2+ from the endoplasmic/sarcoplasmic reticulum (ER/SR). The precise nature of the Ca2+-release event, however, requires fine-tuning for the specific process and type of cell involved. For example, the spatial organization of RyRs, the luminal [Ca2+] and the influence of soluble regulators that fluctuate under physiological and pathophysiological control mechanisms, all affect the amplitude and duration of RyR Ca2+ fluxes. Various proteins are docked tightly to the huge bulky structure of RyR and there is growing evidence that, together, they provide a sophisticated and integrated system for regulating RyR channel gating. This review focuses on those proteins that are relevant to phosphorylation of RyR channels with particular reference to the cardiac isoform of RyR (RyR2). How phosphorylation of RyR affects channel activity and whether proteins such as the FK-506 binding proteins (FKBP12 and FKBP12.6) are involved, have been highly controversial subjects for more than a decade. But that is expected given the large number of participating proteins, the relevance of phosphorylation in heart failure and inherited arrhythmic diseases, and the frustrations of predicting relationships between structure and function before the advent of a high resolution structure of RyR.

Structure and function of seed lipid body-associated proteins

2008 ◽  
Vol 331 (10) ◽  
pp. 746-754 ◽  
Author(s):  
Zita Purkrtova ◽  
Pascale Jolivet ◽  
Martine Miquel ◽  
Thierry Chardot
Keyword(s):  
Lipid Body ◽  
Structure And Function ◽  
Seed Lipid ◽  
Associated Proteins ◽  
And Function

scholarly journals Unique structure and function of viral rhodopsins

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Dmitry Bratanov ◽  
Kirill Kovalev ◽  
Jan-Philipp Machtens ◽  
Roman Astashkin ◽  
Igor Chizhov ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Structure And Function ◽  
Proton Donor ◽  
Dna Viruses ◽  
Host Interactions ◽  
Hydrophobic Barrier ◽  
High Resolution Structure ◽  
Group 2 ◽  
Marine Protists ◽  
And Function

Abstract Recently, two groups of rhodopsin genes were identified in large double-stranded DNA viruses. The structure and function of viral rhodopsins are unknown. We present functional characterization and high-resolution structure of an Organic Lake Phycodnavirus rhodopsin II (OLPVRII) of group 2. It forms a pentamer, with a symmetrical, bottle-like central channel with the narrow vestibule in the cytoplasmic part covered by a ring of 5 arginines, whereas 5 phenylalanines form a hydrophobic barrier in its exit. The proton donor E42 is placed in the helix B. The structure is unique among the known rhodopsins. Structural and functional data and molecular dynamics suggest that OLPVRII might be a light-gated pentameric ion channel analogous to pentameric ligand-gated ion channels, however, future patch clamp experiments should prove this directly. The data shed light on a fundamentally distinct branch of rhodopsins and may contribute to the understanding of virus-host interactions in ecologically important marine protists.

Single-molecule fluorescence-based studies on the dynamics, assembly and catalytic mechanism of the spliceosome

2014 ◽  
Vol 42 (4) ◽  
pp. 1211-1218 ◽  
Author(s):  
Chandani Warnasooriya ◽  
David Rueda
Keyword(s):  
Single Molecule ◽  
Catalytic Mechanism ◽  
Cellular Gene ◽  
Small Nuclear Ribonucleoprotein ◽  
Assembly Kinetics ◽  
Associated Proteins ◽  
Conformational Rearrangements ◽  
Nuclear Ribonucleoprotein ◽  
Mrna Precursor ◽  
Precursor Mrna

Pre-mRNA (precursor mRNA) splicing is a key step in cellular gene expression where introns are excised and exons are ligated together to produce mature mRNA. This process is catalysed by the spliceosome, which consists of five snRNPs (small nuclear ribonucleoprotein particles) and numerous protein factors. Assembly of these snRNPs and associated proteins is a highly dynamic process, making it challenging to study the conformational rearrangements and spliceosome assembly kinetics in bulk studies. In the present review, we discuss recent studies utilizing techniques based on single-molecule detection that have helped overcome this challenge. These studies focus on the assembly dynamics and splicing kinetics in real-time, which help understanding of spliceosomal assembly and catalysis.

scholarly journals Functionally non-redundant paralogs spe-47 and spe-50 encode FB-MO associated proteins and interact with him-8

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0230939
Author(s):  
Jessica N. Clark ◽  
Gaurav Prajapati ◽  
Fermina K. Aldaco ◽  
Thomas J. Sokolich ◽  
Steven S. Keung ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Duplication Event ◽  
Structure And Function ◽  
Sperm Function ◽  
Conserved Sequence ◽  
Long Period ◽  
Normal Sperm ◽  
Number Of Genes ◽  
Associated Proteins ◽  
And Function

The activation of C. elegans spermatids to crawling spermatozoa is affected by a number of genes including spe-47. Here, we investigate a paralog to spe-47: spe-50, which has a highly conserved sequence and expression, but which is not functionally redundant to spe-47. Phylogenetic analysis indicates that the duplication event that produced the paralogs occurred prior to the radiation of the Caenorhabditis species included in the analysis, allowing a long period for the paralogs to diverge in function. Furthermore, we observed that knockout mutations in both genes, either alone or together, have little effect on sperm function. However, hermaphrodites harboring both knockout mutations combined with a third mutation in the him-8 gene are nearly self-sterile due to a sperm defect, even though they have numerous apparently normal sperm within their spermathecae. We suggest that the sperm in these triple mutants are defective in fusing with oocytes, and that the effect of the him-8 mutation is unclear but likely due to its direct or indirect effect on local chromatin structure and function.

Brr2p RNA helicase with a split personality: insights into structure and function

2010 ◽  
Vol 38 (4) ◽  
pp. 1105-1109 ◽  
Author(s):  
Daniela Hahn ◽  
Jean D. Beggs
Keyword(s):  
Domain Architecture ◽  
Rna Helicase ◽  
Structure And Function ◽  
Mrna Splicing ◽  
Eye Disease ◽  
Rna Helicases ◽  
Cellular Processes ◽  
Biochemical Studies ◽  
Split Personality ◽  
And Function

RNA helicases are involved in many cellular processes. Pre-mRNA splicing requires eight different DExD/H-box RNA helicases, which facilitate spliceosome assembly and remodelling of the intricate network of RNA rearrangements that are central to the splicing process. Brr2p, one of the spliceosomal RNA helicases, stands out through its unusual domain architecture. In the present review we highlight the advances made by recent structural and biochemical studies that have important implications for the mechanism and regulation of Brr2p activity. We also discuss the involvement of human Brr2 in retinitis pigmentosa, a degenerative eye disease, and how its functions in splicing might connect to the molecular pathology of the disease.

scholarly journals Characterizing the Structure and Function of the N-Terminus of Schizosaccharomyces Pombe Cdc5, a Pre-Mrna Splicing Factor

2014 ◽  
Vol 106 (2) ◽  
pp. 429a
Author(s):  
Scott E. Collier ◽  
Dungeng Peng ◽  
Markus Voehler ◽  
Nicholas Reiter ◽  
Melanie Ohi
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Structure And Function ◽  
Mrna Splicing ◽  
Splicing Factor ◽  
N Terminus ◽  
And Function

scholarly journals Structure and Function of the Pre-mRNA Splicing Machine

Structure ◽  
2008 ◽  
Vol 16 (11) ◽  
pp. 1605-1615 ◽  
Author(s):  
Joseph Sperling ◽  
Maia Azubel ◽  
Ruth Sperling
Keyword(s):  
Structure And Function ◽  
Mrna Splicing ◽  
And Function
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