AIG1-type guanine nucleotide-binding (G) domain (IPR006703)

Short name: G_AIG1

Overlapping homologous superfamilies

Domain relationships



This entry represents the AIG1-type G domain.

The P-loop guanosine triphosphatases (GTPases) control a multitude of biological processes, ranging from cell division, cell cycling, and signal transduction, to ribosome assembly and protein synthesis. GTPases exert their control by interchanging between an inactive GDP-bound state and an active GTP-bound state, thereby acting as molecular switches. The common denominator of GTPases is the highly conserved guanine nucleotide-binding (G) domain that is responsible for binding and hydrolysis of guanine nucleotides.

The TRAFAC (translation factor related) class AIG1/Toc34/Toc159-like paraseptin GTPase family contains the following subfamilies [PMID: 11916378]:

  • The GTPases of immunity-associated protein (GIMAP)/immune-associated nucleotide-binding protein (IAN) subfamily is conserved among vertebrates and angiosperm plants and has been postulated to regulate apoptosis, particularly in context with diseases such as cancer, diabetes, and infections. The function of GIMAP/IAN GTPases has been linked to self defense in plants and to the development of T cells in vertebrates [PMID: 15474311, PMID: 21059949].
  • Plant-specific Toc (translocon at the outer envelope membrane of chloroplasts) proteins. Toc proteins function as integral components of the chloroplast protein import machinery. The Toc translocon contains the two membrane-bound GTPases Toc33/34 and Toc 159, which expose their G domains to the cytosol and recognise and then deliver precursor proteins through the translocation pore Toc75 [PMID: 17337454, PMID: 18400179].

The GIMAP/IAN GTPases contain a avrRpt2 induced gene 1 (AIG1)-type G domain that exhibits the five motifs G1-G5 characteristic for GTP/GDP-binding proteins. In addition, the AIG-type G domain contains a unique, highly conserved, hydrophobic motif between G3 and G4. It has a divergent version of the guanine recognition motif (G4) at the end of the core strand 5 and an additional helix alpha6 at the C terminus. The AIG1-type G domain contains a central beta-sheet sandwiched by two layers of alpha-helices.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0005525 GTP binding

Cellular Component

No terms assigned in this category.

Contributing signatures

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