Translation initiation factor IF6 (IPR002769)

Short name: eIF6

Overlapping homologous superfamilies


Family relationships



This family includes eukaryotic translation initiation factor 6 (eIF6) as well as presumed archaeal homologues.

The assembly of 80S ribosomes requires joining of the 40S and 60S subunits, which is triggered by the formation of an initiation complex on the 40S subunit. This event is rate-limiting for translation, and depends on external stimuli and the status of the cell. Eukaryotic translation initiation factor 6 (eIF6) binds specifically to the free 60S ribosomal subunit and prevents its association with the 40S ribosomal subunit ribosomes [PMID: 9891075]. Furthermore, eIF6 interacts in the cytoplasm with RACK1, a receptor for activated protein kinase C (PKC). RACK1 is a major component of translating ribosomes, which harbour significant amounts of PKC. Loading 60S subunits with eIF6 caused a dose-dependent translational block and impairment of 80S formation, which are reversed by expression of RACK1 and stimulation of PKC in vivo and in vitro. PKC stimulation leads to eIF6 phosphorylation and its release, promoting 80S subunit formation. RACK1 provides a physical and functional link between PKC signalling and ribosome activation [PMID: 11238882, PMID: 10206977, PMID: 9405604].

All members of this family have a conserved pentameric fold referred to as a beta/alpha propeller. The eukaryotic IF6 members have a moderately conserved C-terminal extension which is not required for ribosomal binding, and may have an alternative function [PMID: 11524672].

GO terms

Biological Process

GO:0042256 mature ribosome assembly

Molecular Function

GO:0043022 ribosome binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.