What do eukaryotic initiation factors do?

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.

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.

What do initiation factors do?

Initiation factors are proteins that bind to the small subunit of the ribosome during the initiation of translation, a part of protein biosynthesis. Initiation factors can interact with repressors to slow down or prevent translation.

What is the function of eIF4F?

Eukaryotic translation initiation factor 4F (eIF4F) is a protein complex that mediates recruitment of ribosomes to mRNA. This event is the rate-limiting step for translation under most circumstances and a primary target for translational control.

What is required for initiation of eukaryotic translation?

Initiation of translation usually involves the interaction of certain key proteins, the initiation factors, with a special tag bound to the 5′-end of an mRNA molecule, the 5′ cap, as well as with the 5′ UTR. These proteins bind the small (40S) ribosomal subunit and hold the mRNA in place.

Where do eukaryotes initiation factors bind?

The eukaryotic translation initiation factor 2 (eIF2) binds to methionyl–transfer RNA (Met–tRNAiMet) when it is bound to GTP and then associates with the 40S ribosomal subunit. After the ribosome finds the start codon, GTP is hydrolyzed by eIF2 and eIF2 bound to GDP is released.

What is mechanism of initiation?

Abstract. Translation initiation is a complex process in which initiator tRNA, 40S, and 60S ribosomal subunits are assembled by eukaryotic initiation factors (eIFs) into an 80S ribosome at the initiation codon of mRNA.

What is 48S initiation complex?

48S initiation complex (48S IC) formation is the first stage in the eukaryotic translation process. According to the canonical mechanism, 40S ribosomal subunit binds to the 5′-end of messenger RNA (mRNA) and scans its 5′-untranslated region (5′-UTR) to the initiation codon where it forms the 48S IC.

Why is eIF4E important?

1 eIF4E structure and function. eIF4E, the cap-binding protein promotes protein synthesis by binding to eIF4G. Beside its role in translation regulation, eIF4E is also important for mRNA stability and the proper subcellular localization of mRNA.

What happens in translation initiation?

Initiation of translation occurs when mRNA, tRNA, and an amino acid meet up inside the ribosome. Once translation has begun, it continues down the line as mRNA shifts along through the ribosome. Each new codon matches with a new tRNA anticodon, bringing in a new amino acid to lengthen the chain.