GABRG2 source guide

GABRG2 contributes the gamma2 subunit to heteromeric GABA-A receptors. The review separates human receptor function, ortholog localization, specific partner assertions and recombinant construct evidence. It contains 74 existing contexts and 31 manually assessed references, with no proposed NEW annotation.

Identity and receptor composition

The reviewed human entry is UniProt P18507. Direct sequences and independent variation reconstruction agree on the displayed long product P18507-2 (475 residues), short P18507-1 (467) and inserted-segment P18507-3 (515). The eight-residue deletion distinguishes the short form. Purification tags and engineered M3–M4 loop replacements are experimental constructs, not natural product definitions. PMID:30602789 Methods explicitly identifies the long P18507-2 backbone despite the UniProt reference-position range 1–467. Native human mass spectrometry reports short and long gamma2, without assigning a splice product to every structural map.

The core is contribution to a GABA-gated chloride channel in a heteromeric GABA-A receptor complex. Gamma2 contributes pore structure and the alpha/gamma benzodiazepine interface. The orthosteric GABA interfaces are principally beta/alpha interfaces; neither an autonomous gamma2 channel nor gamma2-specific GABA binding is asserted. Receptor composition and the chloride gradient constrain physiological interpretation.

Context-specific judgments

The 74 decisions are 47 ACCEPT, 11 KEEP_AS_NON_CORE, 11 MODIFY, 1 UNDECIDED and 4 REMOVE. The original two contributes_to relations are preserved. There are no original extension atoms.

The unresolved context is the human GABARAPL1 partner attributed to PMID:9892355. Its accessible abstract establishes GABARAP association; the later mouse motif study does not independently verify that original human partner record. The source-specific NAS negative-regulation attribution from PMID:33234346 is removed because the inspected source assigns the inhibitory trafficking step to CLPTM1 and other accessory regulators, while gamma2-containing receptors are the regulated target. This does not claim that gamma2 can never influence transmission negatively in another context.

Three positive association contexts have their uninformative generic protein-binding annotations removed; this does not deny the observed interactions. Their exact assay and access scopes remain recorded. The separate unresolved partner context remains UNDECIDED. Histamine responsiveness is a receptor-composition context, not proof of gamma2 histamine binding. Axonal, vesicular and extrasynaptic pools remain distinct from the principal postsynaptic role. PMID:25172774 directly concerns gamma2 transport-vesicle delivery; it is not used to manufacture matching alpha1 or beta3 evidence.

Phylogeny and ontology

The actual retained PTHR18945 tree, alignment, node lookup and IBD records place human P18507 at AN1793/PTN002498426. Seven incoming assertions descend from AN1671/PTN008360627; the plasma-membrane assertion descends from AN7/PTN001054635. All eight origins lie on the target lineage, and none of 14 retained negative family records lies on that lineage. The aligned target matches the 475-residue displayed sequence exactly. Legitimate target self-donation is retained; donor counts are not treated as evidence quality. The incoming plasma-membrane set of 66 donors is older than the 147-donor retained record and remains literal.

Nine refinements follow inspected is_a edges. Postsynaptic membrane within postsynaptic specialization and dendrite membrane within dendrite use part_of, not is_a. The chloride-channel-complex assertion is retained as ACCEPT. Both the original and fresh QuickGO queries return no is_a/part_of path from GABA-A receptor complex to chloride channel complex; that absence does not license replacement of a true claim. The possible ontology relationship is raised as a question. The previous semantic-composition proposal is preserved explicitly as withdrawn in the source evidence. The compact evidence file preserves each row's typed relation and official query URL. These refinements preserve positive biology and do not allege that the broad terms are false.

Reactome and source access

The Reactome975340 reaction was traced through catalyst 975314, complex 975268, set 5340318, heteropentamer 5357502 and gamma set 975308 to entity 975350. The terminal entity names human P18507 residues 40–475 at plasma membrane. This is curated model membership, not an experiment demonstrating every possible subunit combination in vivo.

The normal source union is 41 paths: 35 publications, 3 Reactome records and 3 existing family files. The 31 assessed references comprise 22 publications, 7 GO_REF method documents, one Reactome reaction and UniProt. Unused UniProt bibliography entries are not automatically described as manually read. Existing A1/B2/B3 source blobs remain immutable reuse; the owned PTHR18945 review is excluded. Original 34-path qualification is a dated bounded snapshot. A separate seven-addition check at main b89135d found four immutable-reuse additions and three missing unowned additions; no complete current repository inventory is claimed.

Reference notes below distinguish a native cache from an external original and selected reading from full-paper or image inspection. Full-text availability alone does not mean the entire article, supplements, figures or raw data were read. Initial failed BioC/browser responses are retained as failures. In particular, PMID:15620359's original full text was subsequently found in immutable main and its gamma2 dendritic-surface Results and rat-culture Methods were read.

Manual reference scopes

Preservation and review follow-up

The source evidence preserves all 74 literal raw contexts and the separate actual native mapping, product sequences, phylogenetic summary and exact quotation offsets/hashes. Genuine seeded target fetch produced 74 contexts and all 16 exporter columns matching the retained forecast. All 41 normal sources remain exact: eight immutable main objects, 20 published sibling-source reuses and 13 missing-only acquisitions. Two native titles differ from the private proposal only in GABA(A) punctuation. Cache availability remains separate from the manual reading scopes above.

Four core quotations now anchor the receptor identity, M2 pore lining, beta/alpha GABA interfaces and alpha/gamma flumazenil interface. The original 12-word quote remains unchanged. Total quoted words per source are 24 for PMID:30602789 and 21 for PMID:29950725; the quotes are not repeated in the notes or offset ledger. These are selected exact primary-source anchors, not claims of independent figure or map analysis. The redundant plasma-membrane parent was removed from the core location list; source annotations and the separately supported surface pools remain unchanged.

The first journal entry's statement that positive generic-binding retention followed project policy is corrected by the appended follow-up, while the earlier journal and CREATE record remain intact. Three generic-binding removals concern annotation informativeness, not refutation of the interactions. The source-specific negative-regulation removal remains separately grounded in the cited paper's executor distinction. Scoped-check outcomes and genuine EDIT history are recorded in the notes. No provider research file or existing source cache is rewritten.