LPAR2 literature notes

Scope and research provenance

This pass is restricted to reference discovery, cached-source review, exact-quote extraction, and evidence boundaries. It does not review GO annotation actions or write description/core-function synthesis.

The project deep-research wrapper was attempted with just deep-research-perplexity human LPAR2. It failed on 2026-08-11 with HTTP 401 insufficient_quota and exited without producing LPAR2-deep-research-perplexity.md. No provider-named substitute was created. The literature assessment below was performed manually from project-cached PubMed/PMC, Reactome, GO reference, GOA/IntAct provenance, and UniProt records.

All 21 seeded references were audited: six GO method references, eight seeded PMIDs, and seven Reactome records. Four decisive primary papers were added and fetched through ai-gene-review fetch-pmid: PMID:10729222, PMID:10922489, PMID:15143197, and PMID:16904289. PMID:16904289 was already present in the shared cache. The reviewed UniProt record was also added as a file reference.

Decisive functional evidence

Ligand binding and receptor identity

Gi, Gq, PLC, calcium, and Rho signaling

Receptor-specific scaffolds and interaction boundaries

NHERF2 and PLCB3

TRIP6 and MAGI3

RalA, GRK2, and desensitization

Broad interaction screens

Transcript, sequence, and isoform boundary

Species and experimental-context boundaries

Reference prioritization

The strongest direct sources for later synthesis are PMID:9525886 (human receptor identity, ligand response, Gi/Rho signaling), PMID:9804623 (PLC/IP3/calcium and Gi/Gq), PMID:15143197 (LPAR2-NHERF2-PLCB3 specificity), PMID:16203867 (apical NHERF2-CFTR complex and Gi function), PMID:14688263 (TRIP6), PMID:16904289 (MAGI3), and PMID:19306925 (GRK2-dependent desensitization with strict LPA1/LPAR2 separation).

Full IBA re-review, 2026-09-20

This assessment supersedes earlier universal coupling and membrane-exclusion arguments. All original source rows and qualifiers are preserved. Actual PTHR22750 ancestry places the target below PTN002733616; the target appearing as an IBD source is legitimate experimental grounding. GO cytoplasm includes internal membrane structures, and primary PMID:26473723 demonstrates internalization of human receptor constructs. Conditional cAMP activation from full PMID:10488122 Methods/Results/Fig.7 is retained non-core alongside cell-specific inhibitory responses; a shared focused report is pending. PMID:10727522 provides contrasting assays and human forebrain expression rather than a universal brain absence.

Detailed primary-source access limits, ortholog chains, protein-binding decisions, NEW comparator/ancestor checks and pending questions are in the shared primary evidence record. The companion JSON records live ontology, annotation and tree responses. No additional NEW terms were added.

Recovery PR review: generic binding policy (2026-09-22)

Applied the repository policy to the re-reviewed GO:0005515 rows. Removal concerns
the uninformative function label and does not refute the source interaction.
Rows whose target-specific assays remain inaccessible are UNDECIDED. Source
assertions and supporting evidence are preserved.

Recovery PR signaling follow-up (2026-09-22)

Restore full forskolin context in the quotation, distinguish external full-text access from the abstract-only cache, and retain branch-specific LPAR2 core terms without redundant NEW assertions beneath existing GPCR signaling.