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EIF-2
Eukaryotic Initiation Factor 2 (eIF2) is an eukaryotic initiation factor. It is required for most forms of eukaryotic translation initiation. eIF2 mediates the binding of tRNAiMet to the ribosome in a GTP-dependent manner. eIF2 is a heterotrimer consisting of an alpha (also called subunit 1, EIF2S1), a beta (subunit 2, EIF2S2), and a gamma (subunit 3, EIF2S3) subunit. Once the initiation phase has completed, eIF2 is released from the ribosome bound to GDP as an inactive binary complex. To participate in another round of translation initiation, this GDP must be exchanged for GTP. Function eIF2 is an essential factor for protein synthesis that forms a ternary complex (TC) with GTP and the initiator Met-tRNAiMet. After its formation, the TC binds the 40S ribosomal subunit to form the 43S preinitiation complex (43S PIC). 43S PIC assembly is believed to be stimulated by the initiation factors eIF1, eIF1A, and the eIF3 complex according to ''in vitro'' experiments. The 43S PIC t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guanine Nucleotide Exchange Factor
Guanine nucleotide exchange factors (GEFs) are proteins or protein domains that activate monomeric GTPases by stimulating the release of guanosine diphosphate (GDP) to allow binding of guanosine triphosphate (GTP). A variety of unrelated structural domains have been shown to exhibit guanine nucleotide exchange activity. Some GEFs can activate multiple GTPases while others are specific to a single GTPase. Function Guanine nucleotide exchange factors (GEFs) are proteins or protein domains involved in the activation of small GTPases. Small GTPases act as molecular switches in intracellular signaling pathways and have many downstream targets. The most well-known GTPases comprise the Ras superfamily and are involved in essential cell processes such as cell differentiation and proliferation, cytoskeletal organization, vesicle trafficking, and nuclear transport. GTPases are active when bound to GTP and inactive when bound to GDP, allowing their activity to be regulated by GEFs and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF2S1
Eukaryotic translation initiation factor 2 subunit 1 (eIF2α) is a protein that in humans is encoded by the ''EIF2S1'' gene. Function The protein encoded by this gene is the alpha (α) subunit of the translation initiation factor eIF2 protein complex which catalyzes an early regulated step of protein synthesis initiation, promoting the binding of the initiator tRNA (Met-tRNAiMet) to 40S ribosomal subunits. Binding occurs as a ternary complex of methionyl-tRNA, eIF2, and GTP. eIF2 is composed of 3 nonidentical subunits, alpha (α, 36 kD, this article), beta (β, 38 kD), and gamma (γ, 52 kD). The rate of formation of the ternary complex is modulated by the phosphorylation state of eIF2α. Phosphorylation of eIF2α by EIF-2 kinases plays a key role in regulating the integrated stress response. Clinical significance After reperfusion following brain ischemia, there is inhibition of neuron protein synthesis due to phosphorylation of eIF2α. There is colocalization between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF2S2
Eukaryotic translation initiation factor 2 subunit 2 (eIF2β) is a protein that in humans is encoded by the ''EIF2S2'' gene. Function Eukaryotic translation initiation factor 2 (eIF2) functions in the early steps of protein synthesis by forming a ternary complex with GTP and initiator tRNA and binding to a 40S ribosomal subunit. eIF2 is composed of three subunits, alpha (α), beta (β, this article), and gamma (γ), with the protein encoded by this gene representing the beta subunit. The beta subunit catalyzes the exchange of GDP for GTP, which recycles the eIF2 complex for another round of initiation. Regulation Both eIF2α and eIF2β expression is regulated by the NRF1 transcription factor. See also * eIF2 Eukaryotic Initiation Factor 2 (eIF2) is an eukaryotic initiation factor. It is required for most forms of eukaryotic translation initiation. eIF2 mediates the binding of tRNAiMet to the ribosome in a GTP-dependent manner. eIF2 is a heterotrimer ... References F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF2S3
Eukaryotic translation initiation factor 2 subunit 3 (eIF2γ) is a protein that in humans is encoded by the ''EIF2S3'' gene. Function Eukaryotic translation initiation factor 2 (eIF2) functions in the early steps of protein synthesis by forming a ternary complex with GTP and initiator tRNA and binding to a 40S ribosomal subunit. eIF2 is composed of three subunits, alpha (α), beta (β), and gamma (γ, this article), with the protein encoded by this gene representing the gamma subunit. See also * eIF2 Eukaryotic Initiation Factor 2 (eIF2) is an eukaryotic initiation factor. It is required for most forms of eukaryotic translation initiation. eIF2 mediates the binding of tRNAiMet to the ribosome in a GTP-dependent manner. eIF2 is a heterotrimer ... References Further reading * * * * * * * * * * * * * * * * * {{gene-X-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF2B
eIF2B is a protein complex found in eukaryotes. It is the guanine nucleotide exchange factor for the eukaryotic initiation factor 2 and therefore converts the inactive eIF2-GDP to the active eIF2- GTP. This activation is hindered by phosphorylation of the alpha subunit of eIF2, which leads to a stable eIF2α-P-GDP-eIF2B complex and therefore inhibits translation initiation. Human genes which encode eIF-2B proteins include: * EIF2B1 – alpha subunit (26kDa) * EIF2B2 – beta subunit (39kDa) * EIF2B3 – gamma subunit (58kDa) * EIF2B4 – delta subunit (67kDa) * EIF2B5 Translation initiation factor eIF-2B subunit epsilon is a protein that in humans is encoded by the ''EIF2B5'' gene. Interactions EIF2B5 has been shown to interact with EIF2B2 Translation initiation factor eIF-2B subunit beta is a protein tha ... – epsilon subunit (82kDa) References Protein biosynthesis Gene expression Proteins {{enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF2B4
Translation initiation factor eIF-2B subunit delta is a protein that in humans is encoded by the ''EIF2B4'' gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b .... References Further reading * * * * * * * * * * * * * * * * * * {{gene-2-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF2B5
Translation initiation factor eIF-2B subunit epsilon is a protein that in humans is encoded by the ''EIF2B5'' gene. Interactions EIF2B5 has been shown to interact with EIF2B2 Translation initiation factor eIF-2B subunit beta is a protein that in humans is encoded by the ''EIF2B2'' gene. Function Eukaryotic initiation factor-2B (EIF2B) is a GTP exchange protein essential for protein synthesis. It consists of alpha ( ... and EIF2B1. References Further reading * * * * * * * * * * * * * * * * {{gene-3-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF2B2
Translation initiation factor eIF-2B subunit beta is a protein that in humans is encoded by the ''EIF2B2'' gene. Function Eukaryotic initiation factor-2B (EIF2B) is a GTP exchange protein essential for protein synthesis. It consists of alpha (EIF2B1; MIM 606686), beta (EIF2B2), gamma (EIF2B3; MIM 606273), delta (EIF2B4; MIM 606687), and epsilon (EIF2B5; MIM 603945) subunits. EIF2B activates its EIF2 (see MIM 603907) substrate by exchanging EIF2-bound GDP for GTP. Interactions EIF2B2 has been shown to interact with EIF2B5 and NCK1 Cytoplasmic protein NCK1 is a protein that in humans is encoded by the ''NCK1'' gene. Gene The Nck (non-catalytic region of tyrosine kinase adaptor protein 1) belongs to the adaptor family of proteins. The nck gene was initially isolated from .... References Further reading * * * * * * * * * * * * * * * * * {{gene-14-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF2B1
Translation initiation factor eIF-2B subunit alpha is a protein that in humans is encoded by the ''EIF2B1'' gene. Interactions EIF2B1 has been shown to interact with EIF2B5 Translation initiation factor eIF-2B subunit epsilon is a protein that in humans is encoded by the ''EIF2B5'' gene. Interactions EIF2B5 has been shown to interact with EIF2B2 Translation initiation factor eIF-2B subunit beta is a protein tha .... References Further reading * * * * * * * * * * * * * * * * * {{gene-12-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EIF2B3
Translation initiation factor eIF-2B subunit gamma is a protein that in humans is encoded by the ''EIF2B3'' gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b .... References Further reading * * * * * * * * * * * * * * * * * * * {{gene-1-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GTPase-activating Protein
GTPase-activating proteins or GTPase-accelerating proteins (GAPs) are a family of regulatory proteins whose members can bind to activated G proteins and stimulate their GTPase activity, with the result of terminating the signaling event. GAPs are also known as RGS protein, or RGS proteins,Kimple, A.J. "Structural Determinants of G-protein α Subunit Selectivity by Regulator of G-protein Signaling 2 (RGS2)". ''The Journal of Biological Chemistry''. 284 (2009): 19402-19411. and these proteins are crucial in controlling the activity of G proteins. Regulation of G proteins is important because these proteins are involved in a variety of important cellular processes. The large G proteins, for example, are involved in transduction of signaling from the G protein-coupled receptor for a variety of signaling processes like hormonal signaling, and small G proteins are involved in processes like cellular trafficking and cell cycling. GAP's role in this function is to turn the G protein's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryotic Initiation Factor
Eukaryotic initiation factors (eIFs) are proteins or protein complexes involved in the initiation phase of eukaryotic translation. These proteins help stabilize the formation of ribosomal preinitiation complexes around the start codon and are an important input for post-transcription gene regulation. Several initiation factors form a complex with the small 40S ribosomal subunit and Met-tRNAiMet called the 43S preinitiation complex (43S PIC). Additional factors of the eIF4F complex (eIF4A, E, and G) recruit the 43S PIC to the five-prime cap structure of the mRNA, from which the 43S particle scans 5'-->3' along the mRNA to reach an AUG start codon. Recognition of the start codon by the Met-tRNAiMet promotes gated phosphate and eIF1 release to form the 48S preinitiation complex (48S PIC), followed by large 60S ribosomal subunit recruitment to form the 80S ribosome. There exist many more eukaryotic initiation factors than prokaryotic initiation factors, reflecting the greater ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
