Table of Contents
What does 4E BP1 do?
As one of the two most established mTOR substrates, 4E-BP1 plays a pivotal role in mTORC1 signaling to control translation and cell proliferation.
What does 4EBP1 do?
The mTORC1/S6K/4EBP1 pathway is a major regulator of protein synthesis by phosphorylating several factors in the translational initiation complex, and is thus considered as mainly acting in the cytoplasm [13].
Which eukaryotic initiation factor binds the cap?
Eukaryotic translation initiation factor 4E (eIF4E) binds to the mRNA 5′ cap and brings the mRNA into a complex with other protein synthesis initiation factors and ribosomes.
Does mTOR inhibit 4ebp1?
Importantly, cap-dependent translation reinitiated despite the presence of rapamycin and S6K inhibition through a 4E-BP1 phosphorylation-dependent manner. Finally, we show that catalytic inhibitors of mTOR prevent rapamycin-resistant rephosphorylation of 4E-BP1 supporting their clinical promise.
How many initiation factors are in eukaryotes?
In eukaryotes, at least eleven different initiation factors are required to properly initiate translation. Collectively, they ensure that the methionyl-initiator tRNA (Met-tRNAiMet) is brought in the P site of the ribosome to the initiator AUG of an mRNA.
Does mTOR build muscle?
mTOR controls the anabolic and catabolic signaling of skeletal muscle mass, resulting in the modulation of muscle hypertrophy and muscle wastage. This review will highlight the fundamental role of mTOR in skeletal muscle growth by summarizing the phenotype of skeletal-specific mTOR deficiency.
What is the 5 cap of mRNA?
The 5′ cap structure m7GpppN (where N is any nucleotide) is a ubiquitous feature of cellular eukaryotic mRNAs. The cap is multifunctional as it is involved in translation, nucleocytoplasmic transport, splicing, and stabilization of mRNA against 5′ exonucleolytic degradation.
What is the role of initiation factors IF1 and IF3?
IF-3 is a basic protein that binds to the 30S ribosomal subunit. The chloroplast homolog enhances the poly(A,U,G)-dependent binding of the initiator tRNA to its ribosomal 30s subunits. IF1–IF3 may also perform ribosome recycling….Translation initiation factor IF-3.
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How many initiation factors are present in prokaryotes?
three initiation factors
In bacteria, initiation requires three initiation factors, IF1, IF2, and IF3, and proceeds in three steps.
How do I activate mTOR muscle?
mTORC1 is activated by IGF-I/insulin, mechanical stimulation and amino acids (blue lines) and inhibited by glucocorticoids and myostatin (red lines). Activated mTORC1 increases protein synthesis in skeletal muscle.
What is the advantage of the 5 cap and poly-A tail?
pre-mRNA before they go to the cytoplasm. What is the advantage of the 5′ cap and poly A tail? They seem to facilitate the export of mRNA. They protect mRNA from hydrolytic enzymes.
What is the 3 poly-A tail?
Polyadenylate [poly(A)] tail addition to the 3′ end of a wide range of RNAs is a highly conserved modification that plays a central role in cellular RNA function. Elements for nuclear expression (ENEs) are cis-acting RNA elements that stabilize poly(A) tails by sequestering them in RNA triplex structures.
What is the function of 4EBP1?
Eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1) is a member of a family of translation repressor proteins, and a well-known substrate of mechanistic target of rapamycin (mTOR) signaling pathway. Phosphorylation of 4E-BP1 causes its release from eIF4E to allow cap-dependent translation to proceed.
What is the EIF4EBP1 gene?
EIF4EBP1 (Eukaryotic Translation Initiation Factor 4E Binding Protein 1) is a Protein Coding gene. Diseases associated with EIF4EBP1 include Tuberous Sclerosis and Rhabdomyosarcoma . Among its related pathways are mTOR signalling and AMP-activated Protein Kinase (AMPK) Signaling .
Is 4E-BP1 phosphorylated by other kinases Besides mTOR?
Phosphorylation of 4E-BP1 causes its release from eIF4E to allow cap-dependent translation to proceed. Recently, 4E-BP1 was shown to be phosphorylated by other kinases besides mTOR, and overexpression of 4E-BP1 was found in different human carcinomas.
What does eIF-4E have in common with 4e binding proteins?
Mader S, Lee H, Pause A, Sonenberg N (1995). “The translation initiation factor eIF-4E binds to a common motif shared by the translation factor eIF-4 gamma and the translational repressors 4E-binding proteins”. Mol. Cell. Biol. 15 (9): 4990–7. doi: 10.1128/MCB.15.9.4990.