eIF2B is a protein 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. [1]
Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific three-dimensional structure that determines its activity.
Eukaryotes are organisms whose cells have a nucleus enclosed within membranes, unlike prokaryotes, which have no membrane-bound organelles. Eukaryotes belong to the domain Eukaryota or Eukarya. Their name comes from the Greek εὖ and κάρυον. Eukaryotic cells also contain other membrane-bound organelles such as mitochondria and the Golgi apparatus, and in addition, some cells of plants and algae contain chloroplasts. Unlike unicellular archaea and bacteria, eukaryotes may also be multicellular and include organisms consisting of many cell types forming different kinds of tissue. Animals and plants are the most familiar eukaryotes.
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.
Human genes which encode eIF-2B proteins include:
Translation initiation factor eIF-2B subunit alpha is a protein that in humans is encoded by the EIF2B1 gene.
Translation initiation factor eIF-2B subunit beta is a protein that in humans is encoded by the EIF2B2 gene.
Translation initiation factor eIF-2B subunit gamma is a protein that in humans is encoded by the EIF2B3 gene.
![]() | This enzyme-related article is a stub. You can help Wikipedia by expanding it. |
In molecular biology, housekeeping genes are typically constitutive genes that are required for the maintenance of basic cellular function, and are expressed in all cells of an organism under normal and patho-physiological conditions. Although some housekeeping genes are expressed at relatively constant rates in most non-pathological situations, the expression of other housekeeping genes may vary depending on experimental conditions.
Eukaryotic translation initiation factor 2 subunit 1 (eIF2α) is a protein that in humans is encoded by the EIF2S1 gene.
Translation initiation factor eIF-2B subunit epsilon is a protein that in humans is encoded by the EIF2B5 gene.
Eukaryotic translation initiation factor 3 subunit A (eIF3a) is a protein that in humans is encoded by the EIF3A gene. It is one of the subunits of Eukaryotic initiation factor 3 (eIF3) a multiprotein complex playing major roles in translation initiation in eukaryotes.
Eukaryotic translation initiation factor 2-alpha kinase 3, also known as protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK), is an enzyme that in humans is encoded by the EIF2AK3 gene.
Eukaryotic translation initiation factor 2 subunit 2 (eIF2β) is a protein that in humans is encoded by the EIF2S2 gene.
Translation initiation factor eIF-2B subunit delta is a protein that in humans is encoded by the EIF2B4 gene.
Eukaryotic translation initiation factor 2 subunit 3 (eIF2γ) is a protein that in humans is encoded by the EIF2S3 gene.
Eukaryotic translation initiation factor 3 subunit B (eIF3b) is a protein that in humans is encoded by the EIF3B gene.
Eukaryotic translation initiation factor 3 subunit H (eIF3h) is a protein that in humans is encoded by the EIF3H gene.
Eukaryotic translation initiation factor 3 subunit G (eIF3g) is a protein that in humans is encoded by the EIF3G gene.
Eukaryotic translation initiation factor 2A (eIF2A) is a protein that in humans is encoded by the EIF2A gene. The eIF2A protein is not to be confused with eIF2α, a subunit of the heterotrimeric eIF2 complex. Instead, eIF2A functions by a separate mechanism in eukaryotic translation.
Eukaryotic translation initiation factor 3 subunit F (eIF3f) is a protein that in humans is encoded by the EIF3F gene.
Eukaryotic translation initiation factor 3 subunit D (eIF3d) is a protein that in humans is encoded by the EIF3D gene.
Eukaryotic translation initiation factor 3 subunit J (eIF3j) is a protein that in humans is encoded by the EIF3J gene.
Eukaryotic translation initiation factor 3 subunit K (eIF3k) is a protein that in humans is encoded by the EIF3K gene.