PROSITE documentation PDOC51366
MI domain profile


The MI (after MA-3 and eIF4G) domain is a protein-protein interaction module of ~130 amino acids [1,2,3]. It appears in several translation factors and is found in:

  • One copy in plant and animal eIF4G 1 and 2 (DAP-5/NAT1/p97),
  • Two copies in the animal programmed cell death protein 4 (PDCD4) or MA-3 that is induced during programmed cell death and inhibits neoplastic transformation,
  • Four tandem-repeated copies in a group of uncharacterized plant proteins.

The MI domain consists of seven α-helices, which pack into a globular form (see <PDB:2IOL>). The packing arrangement consists of repeating pairs of antiparallel helices packed one upon the other such that a superhelical axis is generated perpendicular to the α-helical axes [4].

The profile we developed covers the entire MI domain.


The MI domain has also been named MA3 domain.

Last update:

February 2008 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

MI, PS51366; MI domain profile  (MATRIX)


1AuthorsAravind L. Koonin E.V.
TitleEukaryote-specific domains in translation initiation factors: implications for translation regulation and evolution of the translation system.
SourceGenome Res. 10:1172-1184(2000).
PubMed ID10958635

2AuthorsPonting C.P.
TitleNovel eIF4G domain homologues linking mRNA translation with nonsense-mediated mRNA decay.
SourceTrends. Biochem. Sci. 25:423-426(2000).
PubMed ID10973054

3AuthorsYang H.-S. Cho M.-H. Zakowicz H. Hegamyer G. Sonenberg N. Colburn N.H.
TitleA novel function of the MA-3 domains in transformation and translation suppressor Pdcd4 is essential for its binding to eukaryotic translation initiation factor 4A.
SourceMol. Cell. Biol. 24:3894-3906(2004).
PubMed ID15082783

4AuthorsLaRonde-LeBlanc N. Santhanam A.N. Baker A.R. Wlodawer A. Colburn N.H.
TitleStructural basis for inhibition of translation by the tumor suppressor Pdcd4.
SourceMol. Cell. Biol. 27:147-156(2007).
PubMed ID17060447

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