Eukaryotic initiation factors (eIFs) are a group of proteins essential for the initiation of protein synthesis in eukaryotic cells. They play roles in assembling the ribosome and the mRNA (messenger RNA) with the initiator tRNA (transfer RNA) forming the translation initiation complex. EIFs play a central role in recruiting the small 40S ribosomal subunit to the mRNA. The eIF4F complex, consisting of eIF4E (cap-binding protein), eIF4A (RNA helicase), and eIF4G (scaffold protein), promotes binding to the mRNA's 5' cap structure. Cap recognition enables the ribosome to then scan the mRNA for the AUG start codon. After binding to the mRNA's cap, the ribosome, along with associated eIFs, scans along the mRNA in a 5' to 3' direction. Scanning allows the ribosome to locate the start codon and eIF1 and eIF1A help modulate the scanning process ensuring accurate start codon selection. EIF2-GTP and the initiator methionine tRNA (Met-tRNAi), forms a complex which is recruited to the ribosome when it encounters the start codon. eIF5-GTP, together with eIF1, then promotes binding of the complex to the 40S ribosomal subunit. Once the 40S subunit, mRNA, and initiator tRNA are correctly positioned, other eIFs, such as eIF5B and eIF6, facilitate the joining of the 60S ribosomal subunit to form the fully functional 80S ribosome and the beginning of the translational elongation phase. In cap-dependent translation initiation, the eIF4F complex recognizes and binds to the mRNA's 5' cap structure. This interaction allows the small ribosomal subunit to assemble with the mRNA and scan for the start codon. The binding of eIF1, eIF1A, and eIF2-GTP-Met-tRNAi helps ensure accurate start codon selection. Most cellular mRNAs use cap-dependent translation to synthesize proteins. However, cap-independent initiation (via Internal Ribosome Entry Site, IRESs) can also occur. Cap-independent initiation often occurs during stress conditions with viral RNAs and specific cellular mRNAs containing internal ribosome entry sites (IRES), allowing the ribosome to directly bind to the mRNA at a specific site without prior scanning. An example is the IRES-mediated translation initiation in picornaviruses such as poliovirus. eIFs also have regulatory functions in translation. For instance, eIF4E-binding proteins (4E-BPs) can inhibit translation by binding to eIF4E and preventing its interaction with the mRNA cap. This regulation may be important in increased protein synthesis often observed in cancer cells, where activated oncogenic signalling can activate the mTORC1 pathway to stimulate translation by phosphorylating 4E-BPs, releasing eIF4E to initiate translation. During cellular stress, such as amino acid deprivation, eIF2α (a subunit of eIF2) can become phosphorylated, reducing the formation of the ternary complex (eIF2-GTP-Met-tRNAi). This hinders global translation initiation, allowing the cell to conserve energy and respond to stress. The Integrated Stress Response (ISR) is an example of this mechanism, which helps cells adapt to various stressors. Thus, eukaryotic initiation factors are essential components in the process of translation initiation in eukaryotic cells, facilitating the recruitment of ribosomal subunits, mRNA, and initiator tRNA to the start codon and ensuring accurate protein synthesis. We provide a large product catalogue of research tools for studying eukaryotic initiation factors, including eIF4EBP1 antibodies, eIF4E antibodies, PERK antibodies, EIF2S1 antibodies, and eIF4EBP1 ELISA Kits. Explore our full eukaryotic initiation factors product range below and discover more, for less.