| Structural highlights
Disease
[RT22_HUMAN] Hypotonia with lactic acidemia and hyperammonemia. The disease is caused by mutations affecting the gene represented in this entry. [RT16_HUMAN] Combined oxidative phosphorylation defect type 2. The disease is caused by mutations affecting the gene represented in this entry. [RM03_HUMAN] Combined oxidative phosphorylation defect type 9. The disease is caused by mutations affecting the gene represented in this entry. [RM44_HUMAN] Infantile hypertrophic cardiomyopathy due to MRPL44 deficiency. The disease is caused by mutations affecting the gene represented in this entry.
Function
[RRFM_HUMAN] Responsible for the release of ribosomes from messenger RNA at the termination of protein biosynthesis. May increase the efficiency of translation by recycling ribosomes from one round of translation to another (By similarity). [RM14_HUMAN] Forms part of 2 intersubunit bridges in the assembled ribosome. Upon binding to MALSU1 intersubunit bridge formation is blocked, preventing ribosome formation and repressing translation (Probable).[1] [RM36_HUMAN] Component of the large subunit of the mitochondrial ribosome. [G45IP_HUMAN] Acts as a negative regulator of G1 to S cell cycle phase progression by inhibiting cyclin-dependent kinases. Inhibitory effects are additive with GADD45 proteins but occurs also in the absence of GADD45 proteins. Acts as a repressor of the orphan nuclear receptor NR4A1 by inhibiting AB domain-mediated transcriptional activity. May be involved in the hormone-mediated regulation of NR4A1 transcriptional activity. May play a role in mitochondrial protein synthesis. [RM16_HUMAN] Component of the large subunit of mitochondrial ribosome. [PTCD3_HUMAN] Mitochondrial RNA-binding protein that has a role in mitochondrial translation.[2] [RM18_HUMAN] Together with thiosulfate sulfurtransferase (TST), acts as a mitochondrial import factor for the cytosolic 5S rRNA. The precursor form shows RNA chaperone activity; is able to fold the 5S rRNA into an import-competent conformation that is recognized by rhodanese (TST). Both the cytoplasmic and mitochondrial forms are able to bind to the helix IV-loop D in the gamma domain of the 5S rRNA.[3] [ICT1_HUMAN] Essential peptidyl-tRNA hydrolase component of the mitochondrial large ribosomal subunit. Acts as a codon-independent translation release factor that has lost all stop codon specificity and directs the termination of translation in mitochondrion, possibly in case of abortive elongation. May be involved in the hydrolysis of peptidyl-tRNAs that have been prematurely terminated and thus in the recycling of stalled mitochondrial ribosomes.[4] [RT29_HUMAN] Involved in mediating interferon-gamma-induced cell death. [AKIP_HUMAN] May act as a negative regulator of Aurora-A kinase, by down-regulation through proteasome-dependent degradation. [RM41_HUMAN] Component of the mitochondrial ribosome large subunit. Also involved in apoptosis and cell cycle. Enhances p53/TP53 stability, thereby contributing to p53/TP53-induced apoptosis in response to growth-inhibitory condition. Enhances p53/TP53 translocation to the mitochondria. Has the ability to arrest the cell cycle at the G1 phase, possibly by stabilizing the CDKN1A and CDKN1B (p27Kip1) proteins.[5] [6] [RM44_HUMAN] Component of the 39S subunit of mitochondrial ribosome. May have a function in the assembly/stability of nascent mitochondrial polypeptides exiting the ribosome.[7]
Publication Abstract from PubMed
Mammalian mitochondrial ribosomes (mitoribosomes) are responsible for synthesizing proteins that are essential for oxidative phosphorylation (ATP generation). Despite their common ancestry with bacteria, the composition and structure of the human mitoribosome and its translational factors are significantly different from those of their bacterial counterparts. The mammalian mitoribosome recycling factor (RRFmt) carries a mito-specific N terminus extension (NTE), which is necessary for the function of RRFmt Here we present a 3.9-A resolution cryo-electron microscopic (cryo-EM) structure of the human 55S mitoribosome-RRFmt complex, which reveals alpha-helix and loop structures for the NTE that makes multiple mito-specific interactions with functionally critical regions of the mitoribosome. These include ribosomal RNA segments that constitute the peptidyl transferase center (PTC) and those that connect PTC with the GTPase-associated center and with mitoribosomal proteins L16 and L27. Our structure reveals the presence of a tRNA in the pe/E position and a rotation of the small mitoribosomal subunit on RRFmt binding. In addition, we observe an interaction between the pe/E tRNA and a mito-specific protein, mL64. These findings help understand the unique features of mitoribosome recycling.
Structural insights into unique features of the human mitochondrial ribosome recycling.,Koripella RK, Sharma MR, Risteff P, Keshavan P, Agrawal RK Proc Natl Acad Sci U S A. 2019 Apr 8. pii: 1815675116. doi:, 10.1073/pnas.1815675116. PMID:30962385[8]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Hauser R, Pech M, Kijek J, Yamamoto H, Titz B, Naeve F, Tovchigrechko A, Yamamoto K, Szaflarski W, Takeuchi N, Stellberger T, Diefenbacher ME, Nierhaus KH, Uetz P. RsfA (YbeB) proteins are conserved ribosomal silencing factors. PLoS Genet. 2012;8(7):e1002815. doi: 10.1371/journal.pgen.1002815. Epub 2012 Jul , 19. PMID:22829778 doi:10.1371/journal.pgen.1002815
- ↑ Davies SM, Rackham O, Shearwood AM, Hamilton KL, Narsai R, Whelan J, Filipovska A. Pentatricopeptide repeat domain protein 3 associates with the mitochondrial small ribosomal subunit and regulates translation. FEBS Lett. 2009 Jun 18;583(12):1853-8. Epub 2009 May 8. PMID:19427859 doi:http://dx.doi.org/S0014-5793(09)00357-3
- ↑ Smirnov A, Entelis N, Martin RP, Tarassov I. Biological significance of 5S rRNA import into human mitochondria: role of ribosomal protein MRP-L18. Genes Dev. 2011 Jun 15;25(12):1289-305. doi: 10.1101/gad.624711. PMID:21685364 doi:http://dx.doi.org/10.1101/gad.624711
- ↑ Richter R, Rorbach J, Pajak A, Smith PM, Wessels HJ, Huynen MA, Smeitink JA, Lightowlers RN, Chrzanowska-Lightowlers ZM. A functional peptidyl-tRNA hydrolase, ICT1, has been recruited into the human mitochondrial ribosome. EMBO J. 2010 Mar 17;29(6):1116-25. doi: 10.1038/emboj.2010.14. Epub 2010 Feb 25. PMID:20186120 doi:http://dx.doi.org/10.1038/emboj.2010.14
- ↑ Yoo YA, Kim MJ, Park JK, Chung YM, Lee JH, Chi SG, Kim JS, Yoo YD. Mitochondrial ribosomal protein L41 suppresses cell growth in association with p53 and p27Kip1. Mol Cell Biol. 2005 Aug;25(15):6603-16. PMID:16024796 doi:http://dx.doi.org/25/15/6603
- ↑ Kim MJ, Yoo YA, Kim HJ, Kang S, Kim YG, Kim JS, Yoo YD. Mitochondrial ribosomal protein L41 mediates serum starvation-induced cell-cycle arrest through an increase of p21(WAF1/CIP1). Biochem Biophys Res Commun. 2005 Dec 16;338(2):1179-84. Epub 2005 Oct 21. PMID:16256947 doi:http://dx.doi.org/10.1016/j.bbrc.2005.10.064
- ↑ Carroll CJ, Isohanni P, Poyhonen R, Euro L, Richter U, Brilhante V, Gotz A, Lahtinen T, Paetau A, Pihko H, Battersby BJ, Tyynismaa H, Suomalainen A. Whole-exome sequencing identifies a mutation in the mitochondrial ribosome protein MRPL44 to underlie mitochondrial infantile cardiomyopathy. J Med Genet. 2013 Mar;50(3):151-9. doi: 10.1136/jmedgenet-2012-101375. Epub 2013 , Jan 12. PMID:23315540 doi:http://dx.doi.org/10.1136/jmedgenet-2012-101375
- ↑ Koripella RK, Sharma MR, Risteff P, Keshavan P, Agrawal RK. Structural insights into unique features of the human mitochondrial ribosome recycling. Proc Natl Acad Sci U S A. 2019 Apr 8. pii: 1815675116. doi:, 10.1073/pnas.1815675116. PMID:30962385 doi:http://dx.doi.org/10.1073/pnas.1815675116
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