IFT81 notes (human, Q8WYA0)

Deep research status

Falcon deep research succeeded on the second attempt (IFT81-deep-research-falcon.md; first run failed with falcon 429/timeout and an unavailable perplexity-lite fallback; rerun with --timeout 2400). It concurs with the tubulin-module model [file:human/IFT81/IFT81-deep-research-falcon.md "Depleting IFT81 in human RPE-1 cells strongly reduced primary-cilium formation; siRNA-resistant wild-type IFT81 restored it, whereas a mutant disrupting the full tubulin-binding patch failed to rescue."] and adds Boegholm et al. 2023 (not cached): the IFT81-IFT74 coiled coil stimulates RabL2 GTP hydrolysis [file:human/IFT81/IFT81-deep-research-falcon.md "The activity explains RabL2 inactivation and release shortly after IFT initiation."]. This supports MODIFY of RABL2B 'protein binding' rows to small GTPase binding; a GTPase activator annotation is raised as a question rather than asserted (data mainly from Chlamydomonas proteins). It also cites Perrault 2015 (NPHP with polydactyly, IFT81 variants).

Summary

Key curation decisions

HPA cilium atlas vs module role

HPA v25: Primary cilium (Approved), Basal body (Approved), Centrosome (Approved); main location Cytosol. The cytosolic main call reflects the large unassembled/cytoplasmic pool; ciliary and basal body calls fit the IFT-B role. No GO_REF:0000052 rows. Module role "IFT-B core; tubulin binding" and role_description "IFT81-IFT74 bind tubulin cargo" are fully consistent with core_functions (MF tubulin binding; intraciliary transport involved in cilium assembly; anterograde IFT; IFT-B complex). IFT81 (with IFT74) is the one IFT-B subunit pair for which the module's "IFT cargo adaptor" function is directly demonstrated.

Shared IFT background

GOA curation issue common to all IFT-B subunits

Every IFT-B subunit annotated from PMID:26980730 (Katoh et al. 2016, an IFT-B architecture paper) carries an IDA to GO:0030991 intraciliary transport particle A. This contradicts the paper's own content (which supports the GO:0030992 IFT-B IPI rows from the same paper) and the established biochemistry. Marked REMOVE as a genuinely contradicted claim (likely batch term-selection error), not as second-guessing assay data.