6mtd
From Proteopedia
Rabbit 80S ribosome with eEF2 and SERBP1 (unrotated state with 40S head swivel)
Structural highlights
Disease[RS24_HUMAN] Blackfan-Diamond disease. Diamond-Blackfan anemia 3 (DBA3) [MIM:610629]: A form of Diamond-Blackfan anemia, a congenital non-regenerative hypoplastic anemia that usually presents early in infancy. Diamond-Blackfan anemia is characterized by a moderate to severe macrocytic anemia, erythroblastopenia, and an increased risk of developing leukemia. 30 to 40% of Diamond-Blackfan anemia patients present with short stature and congenital anomalies, the most frequent being craniofacial (Pierre-Robin syndrome and cleft palate), thumb and urogenital anomalies. Note=The disease is caused by mutations affecting the gene represented in this entry.[1] Function[RL23A_BOVIN] Component of the ribosome, a large ribonucleoprotein complex responsible for the synthesis of proteins in the cell. Binds a specific region on the 26S rRNA (By similarity). May promote p53/TP53 degradation possibly through the stimulation of MDM2-mediated TP53 polyubiquitination (By similarity).[UniProtKB:P62750] [RS3_CANLF] Involved in translation as a component of the 40S small ribosomal subunit. Has endonuclease activity and plays a role in repair of damaged DNA. Cleaves phosphodiester bonds of DNAs containing altered bases with broad specificity and cleaves supercoiled DNA more efficiently than relaxed DNA. Displays high binding affinity for 7,8-dihydro-8-oxoguanine (8-oxoG), a common DNA lesion caused by reactive oxygen species (ROS). Has also been shown to bind with similar affinity to intact and damaged DNA. Stimulates the N-glycosylase activity of the base excision protein OGG1. Enhances the uracil excision activity of UNG1. Also stimulates the cleavage of the phosphodiester backbone by APEX1. When located in the mitochondrion, reduces cellular ROS levels and mitochondrial DNA damage. Has also been shown to negatively regulate DNA repair in cells exposed to hydrogen peroxide. Plays a role in regulating transcription as part of the NF-kappa-B p65-p50 complex where it binds to the RELA/p65 subunit, enhances binding of the complex to DNA and promotes transcription of target genes. Represses its own translation by binding to its cognate mRNA. Binds to and protects TP53/p53 from MDM2-mediated ubiquitination. Involved in spindle formation and chromosome movement during mitosis by regulating microtubule polymerization. Involved in induction of apoptosis through its role in activation of CASP8. Induces neuronal apoptosis by interacting with the E2F1 transcription factor and acting synergistically with it to up-regulate pro-apoptotic proteins BCL2L11/BIM and HRK/Dp5. Interacts with TRADD following exposure to UV radiation and induces apoptosis by caspase-dependent JNK activation.[UniProtKB:P23396] [RS24_HUMAN] Required for processing of pre-rRNA and maturation of 40S ribosomal subunits.[2] [RS23_BOVIN] Component of the ribosome, a large ribonucleoprotein complex responsible for the synthesis of proteins in the cell. The small ribosomal subunit (SSU) binds messenger RNAs (mRNAs) and translates the encoded message by selecting cognate aminoacyl-transfer RNA (tRNA) molecules. The large subunit (LSU) contains the ribosomal catalytic site termed the peptidyl transferase center (PTC), which catalyzes the formation of peptide bonds, thereby polymerizing the amino acids delivered by tRNAs into a polypeptide chain. The nascent polypeptides leave the ribosome through a tunnel in the LSU and interact with protein factors that function in enzymatic processing, targeting, and the membrane insertion of nascent chains at the exit of the ribosomal tunnel. Plays an important role in translational accuracy.[UniProtKB:P62266] [G1SS70_RABIT] May play a role during erythropoiesis through regulation of transcription factor DDIT3.[HAMAP-Rule:MF_03122] [RS27_BOVIN] Component of the small ribosomal subunit (By similarity). Required for proper rRNA processing and maturation of 18S rRNAs (By similarity).[UniProtKB:P42677] [RLA0_PIG] Ribosomal protein P0 is the functional equivalent of E.coli protein L10. [U3KPD5_RABIT] Binds to the 23S rRNA.[RuleBase:RU000576] Publication Abstract from PubMedThe cellular levels and activities of ribosomes directly regulate gene expression during numerous physiological processes. The mechanisms that globally repress translation are incompletely understood. Here, we use electron cryomicroscopy to analyze inactive ribosomes isolated from mammalian reticulocytes, the penultimate stage of red blood cell differentiation. We identify two types of ribosomes that are translationally repressed by protein interactions. The first comprises ribosomes sequestered with elongation factor 2 (eEF2) by SERPINE mRNA binding protein 1 (SERBP1) occupying the ribosomal mRNA entrance channel. The second type are translationally repressed by a novel ribosome-binding protein, interferon-related developmental regulator 2 (IFRD2), which spans the P and E sites and inserts a C-terminal helix into the mRNA exit channel to preclude translation. IFRD2 binds ribosomes with a tRNA occupying a noncanonical binding site, the 'Z site', on the ribosome. These structures provide functional insights into how ribosomal interactions may suppress translation to regulate gene expression. Structures of translationally inactive mammalian ribosomes.,Brown A, Baird MR, Yip MC, Murray J, Shao S Elife. 2018 Oct 24;7. pii: 40486. doi: 10.7554/eLife.40486. PMID:30355441[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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