# HISTORY
24 Mar 2016: Updated by: TOUCHUP-v1.15
14 Mar 2016: Updated by: TOUCHUP-v1.12

# molecular_function
20140221: Eukaryota_PTN000012953 has function ATP-gated ion channel activity (GO:0035381) 
20140221: Eukaryota_PTN000012953 has function purinergic nucleotide receptor activity (GO:0001614) 
20140221: Opisthokonta_PTN000804619 has function extracellular ATP-gated cation channel activity (GO:0004931) 

# cellular_component
20140221: Eukaryota_PTN000012953 is found in integral component of membrane (GO:0016021) 
20140221: Opisthokonta_PTN000804619 is found in integral component of nuclear inner membrane (GO:0005639) 

# biological_process
20110301: Eukaryota_PTN000012953 participates in cation transport (GO:0006812) 

# WARNINGS - THE FOLLOWING HAVE BEEN REMOVED FOR THE REASONS NOTED

# NOTES
MF: Propagated both GO:4931 extracellular ATP-gated cation channel activity and GO: 1614 purinergic nucleotide receptor activity to AN0 as most of the members of the family have experimental annotations to these terms.
- PG Feb 21 2014: Fixed annotation to remove the 'extracellular' activity annotation from the Dicty branch, because accroding to PMID:19833731 "all five dP2X proteins proved to be intracellular, localized to the contractile
vacuole membrane with the ligand binding domain facing the lumen.". Not
BP: Propagated GO:6812 cation transport to AN0. Most of the other annotations are to very granular terms and cation transport seem to fit the molecualar function of these proteins.
CC: Propagated GO:16020 to AN0 because being involved in transport, that seems to be an obvious location.

# REFERENCE
Annotation inferences using phylogenetic trees
The goal of the GO Reference Genome Project, described in PMID 19578431, is to provide accurate, complete and consistent GO annotations for all genes in twelve model organism genomes. To this end, GO curators are annotating evolutionary trees from the PANTHER database with GO terms describing molecular function, biological process and cellular component. GO terms based on experimental data from the scientific literature are used to annotate ancestral genes in the phylogenetic tree by sequence similarity (ISS), and unannotated descendants of these ancestral genes are inferred to have inherited these same GO annotations by descent. The annotations are done using a tool called PAINT (Phylogenetic Annotation and INference Tool).