eIF2B is a

protein complex A protein complex or multiprotein complex is a group of two or more associated polypeptide chains. Protein complexes are distinct from multienzyme complexes, in which multiple catalytic domains are found in a single polypeptide chain. Protein ...

found in

eukaryote Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bact ...

s. It is the

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 struct ...

for the eukaryotic initiation factor 2 and therefore converts the inactive eIF2-

GDP Gross domestic product (GDP) is a monetary measure of the market value of all the final goods and services produced and sold (not resold) in a specific time period by countries. Due to its complex and subjective nature this measure is of ...

to the active eIF2- GTP. This activation is hindered by

phosphorylation In chemistry, phosphorylation is the attachment of a phosphate group to a molecule or an ion. This process and its inverse, dephosphorylation, are common in biology and could be driven by natural selection. Text was copied from this source, ...

of the alpha subunit of eIF2, which leads to a stable eIF2α-P-GDP-eIF2B complex and therefore inhibits

translation Translation is the communication of the Meaning (linguistic), meaning of a #Source and target languages, source-language text by means of an Dynamic and formal equivalence, equivalent #Source and target languages, target-language text. The ...

initiation. Human genes which encode eIF-2B proteins include: * EIF2B1 – alpha subunit (26kDa) *

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 ( ...

– 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