{PDOC51484}
{PS51484; G8}
{BEGIN}
*********************
* G8 domain profile *
*********************

The G8  (for  eight  conserved glycine residues) domain is widely distributed,
being found   in   proteins  from  various  animals  (from  Strongylocentrotus
purpuratus to   Homo   sapiens),   lower  eukaryotes  (such  as  Dictyostelium
discoideum and  Tetrahymena  thermophila)  and  bacteria  (such  as the alpha-
proteobacteria Nitrobacter    hamburgensis,    gamma-proteobacterium   Hahella
chejuensis and  the  green  non-sulfur bacterium Chloroflexus aurantiacus) but
absent in  plants,  viruses  and  archaea.  Many  G8-containing  proteins  are
integral membrane proteins with signal peptides and/or transmembrane segments,
and others  lacking  TM  domain may be secreted. Several other protein domains
frequently co-occur  in  proteins  with a G8 domain. These include the IPT/TIG
domain, the  GG  domain  and the PbH1 repeat. Many G8-containing proteins have
been associated  with  diseases  such  as  polycystic  kidney disease and non-
syndromic hearing  loss. The G8 domain may be involved in extracellular ligand
binding and progress of catalysis [1].

The G8  domain  is  about  120  amino  acids residues in length. The secondary
structure prediction  of  the  G8  domain  suggests  that it contains 10 beta-
strands and 1 helix. These strands are separated by conserved glycine residues
and contain  some  conserved  hydrophobic  residues.  Based  on the structural
prediction, the  conserved  glycine residues and hydrophobic residues might be
important for  correct  folding  of  G8 domains, the glycine residues allowing
rotation in  the  backbone  and  hydrophobic  interactions  among  hydrophobic
residues on beta-strands/helix contributing to structural stabilization [1].

Some proteins known to contain a G8 domain are listed below:

 - Human  PKHD1  protein  (also  known as fibrocystin and polyductin), a large
   membrane protein  involved  in  autosomal  recessive  polycystic kidney and
   hepatic disease.
 - Human  KIAA1199,  an  inner-ear-specific  protein  expressed in cochlea and
   vestibule tissues
 - Human TMEM2, a protein expressed in cochlea and a variety of other tissues.

The profile we developed covers the entire G8 domain.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.
-Last update: March 2010 / First entry.

[ 1] He Q.-Y., Liu X.-H., Li Q., Studholme D.J., Li X.-W., Liang S.-P.
     "G8: a novel domain associated with polycystic kidney disease and
     non-syndromic hearing loss."
     Bioinformatics 22:2189-2191(2006).
     PubMed=16632497; DOI=10.1093/bioinformatics/btl123

--------------------------------------------------------------------------------
PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and
distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives
(CC BY-NC-ND 4.0) License, see https://prosite.expasy.org/prosite_license.html
--------------------------------------------------------------------------------

{END}