Article · Wikipedia archive · Last revised Jun 9, 2026

EIF2B

eIF2B is a protein complex 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.

Last revised
Jun 9, 2026
Read time
≈ 1 min
Length
111 w
Citations
1
Source
Wikipedia ↗

eIF2B is a protein complex 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

Human genes which encode eIF-2B proteins include:

  • EIF2B1 – alpha subunit (26kDa)
  • EIF2B2 – beta subunit (39kDa)
  • EIF2B3 – gamma subunit (58kDa)
  • EIF2B4 – delta subunit (67kDa)
  • EIF2B5 – epsilon subunit (82kDa)
References

References

  1. Pavitt, G.D. (Dec 2005). "eIF2B, a mediator of general and gene-specific translational control". Biochem Soc Trans. 33 (Pt 6): 1487–92. doi:10.1042/BST20051487. PMID 16246152.