TRIM21

Tripartite motif-containing 21

Crystallographic structure of two molecules of the C-terminal PRYSPRY domain of TRIM21 (top right and top left) complexed with homodimeric Ig gamma-1 chain C region (center). Each chain is individually rainbow colored (N-terminus = blue, C-terminus = red).[1]
Identifiers
Symbols TRIM21; SSA; RNF81; RO52; SSA1
External IDs OMIM: 109092 MGI: 106657 HomoloGene: 2365 GeneCards: TRIM21 Gene
EC number 6.3.2.-
RNA expression pattern
More reference expression data
Orthologs
Species Human Mouse
Entrez 6737 20821
Ensembl ENSG00000132109 ENSMUSG00000030966
UniProt P19474 Q3U7K7
RefSeq (mRNA) NM_003141 XM_991802
RefSeq (protein) NP_003132 XP_996896
Location (UCSC) Chr 11:
4.36 – 4.37 Mb		 Chr 7:
102.43 – 102.44 Mb
PubMed search [1] [2]

Tripartite motif-containing protein 21 also known as E3 ubiquitin-protein ligase TRIM21 is a protein that in humans is encoded by the TRIM21 gene.[2][3] Alternatively spliced transcript variants for this gene have been described but the full-length nature of only one has been determined. It is expressed in most human tissues.[4]

Contents

Structure

TRIM21 is a member of the tripartite motif (TRIM) family. The TRIM motif includes three zinc-binding domains, a RING finger domain, a B-box type 1 and a B-box type 2 zinc finger, and a coiled coil region.[3]

Function

TRIM21 is an intracellular antibody effector in the intracellular antibody-mediated proteolysis pathway. It binds to immunoglobulin G as well as immunoglobulin M on antibody marked non-enveloped virions which have infected the cell. Either by autoubiquitination or by ubiquitination of a cofactor, it is then responsible for directing the virions to the proteasome. TRIM21 itself is not degraded in the proteasome unlike both the viral capsid and the bound antibody.[4]

TRIM21 is part of the RoSSA ribonucleoprotein, which includes a single polypeptide and one of four small RNA molecules. The RoSSA particle localizes to both the cytoplasm and the nucleus.[3]

Clinical significance

RoSSA interacts with autoantigens in patients with Sjögren's syndrome and systemic lupus erythematosus.[3]

References

  1. ^ PDB 2IWG; James LC, Keeble AH, Khan Z, Rhodes DA, Trowsdale J (April 2007). "Structural basis for PRYSPRY-mediated tripartite motif (TRIM) protein function". Proc. Natl. Acad. Sci. U.S.A. 104 (15): 6200–5. doi:10.1073/pnas.0609174104. PMC 1851072. PMID 17400754. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1851072. 
  2. ^ Frank MB, Itoh K, Fujisaku A, Pontarotti P, Mattei MG, Neas BR (Mar 1993). "The mapping of the human 52-kD Ro/SSA autoantigen gene to human chromosome 11, and its polymorphisms". Am J Hum Genet 52 (1): 183–91. PMC 1682114. PMID 8094596. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1682114. 
  3. ^ a b c d "Entrez Gene: TRIM21 tripartite motif-containing 21". http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=6737. 
  4. ^ a b Mallery DL, McEwan WA, Bidgood SR, Towers GJ, Johnson CM, James LC (2010). "Antibodies mediate intracellular immunity through tripartite motif-containing 21 (TRIM21)". Proc. Natl. Acad. Sci. U.S.A. 107 (46): 19985–19990. doi:10.1073/pnas.1014074107. PMC 2993423. PMID 21045130. http://www.pnas.org/content/early/2010/11/01/1014074107. 


Further reading