Tripartite motif-containing protein 25 is a protein that in humans is encoded by the TRIM25 gene. [5] [6]
The protein encoded by this gene is a member of the tripartite motif (TRIM) family grouping more than 70 TRIMs. TRIM proteins primarily function as ubiquitin ligases that regulate the innate response to infection. [7] TRIM25 localizes to the cytoplasm. The presence of potential DNA-binding and dimerization-transactivation domains suggests that this protein may act as a transcription factor, similar to several other members of the TRIM family. Expression of the gene is upregulated in response to estrogen, and it is thought to mediate estrogen actions in breast cancer as a primary response gene. [6]
TRIM25 has an N-terminal RING domain, followed by a B-box type 1 domain, a B-box type 2 domain, a coiled-coil domain (CCD) and a C-terminal SPRY domain. The RING domain coordinates two zinc atoms and is essential for recruiting ubiquitin-conjugating enzymes. The function of the B-box domains is unknown. The CCD domain has been implicated in multimerization and other protein-protein interactions. [8] The SPRY domain is required for substrate recruitment. [9] The NMR chemical shifts for backbone of the PRYSPRY domain of TRIM25 is assigned based on triple-resonance experiments using uniformly isotopic labeled protein and the secondary structure of the domain PRYSPRY domain of TRIM25 predicted based on the NMR assignments. [10]
TRIM25 plays a key role in the RIG-I signaling pathway. RIG-I is a cytosolic pattern recognition receptor that senses viral RNA. Following RNA recognition, the caspase recruitment domain (CARD) of RIG-I undergoes K(63)-linked ubiquitination by TRIM25. The RING and SPRY domains of TRIM25 mediate its interaction with RIG-I. IFN production then follows by an intracellular signaling pathway involving IRF3. [11]
To avoid IFN production, the non structural protein (NS1) of influenza will interact with CCD domain of TRIM25 to block RIG-I ubiquitination. Some studies have shown that a deletion of the CCD domain of TRIM25 prevents the binding of NS1. [12] Without this ubiquitination, there won’t be IFN production.
Ubiquitin is a small regulatory protein found in most tissues of eukaryotic organisms, i.e., it is found ubiquitously. It was discovered in 1975 by Gideon Goldstein and further characterized throughout the late 1970s and 1980s. Four genes in the human genome code for ubiquitin: UBB, UBC, UBA52 and RPS27A.
Mouse double minute 2 homolog (MDM2) also known as E3 ubiquitin-protein ligase Mdm2 is a protein that in humans is encoded by the MDM2 gene. Mdm2 is an important negative regulator of the p53 tumor suppressor. Mdm2 protein functions both as an E3 ubiquitin ligase that recognizes the N-terminal trans-activation domain (TAD) of the p53 tumor suppressor and as an inhibitor of p53 transcriptional activation.
E3 SUMO-protein ligase PIAS3 is an enzyme that in humans is encoded by the PIAS3 gene.
E3 ubiquitin-protein ligase SMURF1 is an enzyme that in humans is encoded by the SMURF1 gene. The SMURF1 Gene encodes a protein with a size of 757 amino acids and the molecular mass of this protein is 86114 Da.
Ubiquitin-conjugating enzyme E2 D2 is a protein that in humans is encoded by the UBE2D2 gene.
Tripartite motif-containing protein 37 is an E3 ubiquitin ligase in humans that is encoded by the TRIM37 gene.
Ubiquitin/ISG15-conjugating enzyme E2 L6 is a protein that in humans is encoded by the UBE2L6 gene.
RING finger and CHY zinc finger domain-containing protein 1 is a protein that in humans is encoded by the RCHY1 gene.
The human gene UBR1 encodes the enzyme ubiquitin-protein ligase E3 component n-recognin 1.
Transcription factor E4F1 is a protein that in humans is encoded by the E4F1 gene.
E3 ubiquitin-protein ligase RNF14 is an enzyme that in humans is encoded by the RNF14 gene.
Ubiquitin-conjugating enzyme E2 G1 is a protein that in humans is encoded by the UBE2G1 gene.
Ubiquitin-conjugating enzyme E2 E1 is a protein that in humans is encoded by the UBE2E1 gene.
E3 ubiquitin-protein ligase RNF8 is an enzyme that in humans is encoded by the RNF8 gene. RNF8 has activity both in immune system functions and in DNA repair.
RanBP-type and C3HC4-type zinc finger-containing protein 1 is a protein that in humans is encoded by the RBCK1 gene.
Zinc finger protein 318 is a protein that in humans is encoded by the ZNF318 gene.
E3 ubiquitin-protein ligase RFWD2 is an enzyme that in humans is encoded by the RFWD2 gene.
Cytochrome c oxidase subunit 7A-related protein, mitochondrial is an enzyme that in humans is encoded by the COX7A2L gene.
E3 ubiquitin-protein ligase RNF125 is an enzyme that in humans is encoded by the RNF125 gene.
RIG-I-like receptors are a type of intracellular pattern recognition receptor involved in the recognition of viruses by the innate immune system. RIG-I is the best characterized receptor within the RIG-I like receptor (RLR) family. Together with MDA5 and LGP2, this family of cytoplasmic pattern recognition receptors (PRRs) are sentinels for intracellular viral RNA that is a product of viral infection. The RLR receptors provide frontline defence against viral infections in most tissues.