PICALM curation notes

2026-06-19

• Deep-research attempt with just deep-research-falcon human PICALM --fallback perplexity-lite timed out after 180 seconds with no generated research artifact, so this manual review uses cached UniProt, GOA, Reactome, and publication evidence.
• PICALM/CALM is a phosphatidylinositol-binding clathrin assembly adaptor. The core function is clathrin-mediated endocytosis: CALM binds clathrin heavy chain, localizes to plasma membrane clathrin-coated pits, and affects transferrin/EGF receptor endocytosis and clathrin recruitment PMID:10436022.
• Depletion data support a direct role in clathrin coat formation rather than just a passive localization marker. CALM knockdown produced enlarged/abnormal clathrin structures and the abstract concludes a critical role in orderly coated bud formation at the plasma membrane PMID:16262731.
• The ANTH/PIP2-linked membrane-curvature function is core. CALM depletion altered CCP/CCV maturation and size, and the N-terminal helix was required for rescue of normal vesicle size/maturation PMID:25898166.
• SNARE cargo sorting is core. CALM/PICALM directly binds small R-SNAREs VAMP8, VAMP3, and VAMP2 and is needed for their endocytosis, explaining the SNARE binding, synaptic vesicle, and vesicle cargo loading annotations PMID:22118466.
• Alzheimer and brain endothelial annotations are important but mostly non-core relative to the evolved adapter function. PICALM regulates amyloid-beta/LRP1 internalization and transcytosis across BBB endothelial cells, with reduced PICALM in AD endothelium and impaired amyloid-beta efflux in Picalm-deficient mice PMID:26005850. I kept these as non-core disease-context/cargo-specific annotations.
• APP/gamma-secretase annotations are supported as cargo-specific consequences of clathrin-mediated trafficking, not a separate catalytic role: CALM depletion changes gamma-secretase localization and A-beta species ratio PMID:24577224.
• Iron-homeostasis annotations are supported by Picalm-deficient MEF and mouse data, but they are downstream of transferrin receptor endocytosis rather than a distinct molecular activity PMID:22952941.
• Tau/neurofibrillary tangle annotations are Alzheimer-relevant but non-core. The cached abstract supports PICALM association with tau pathology and co-immunoprecipitation with PHF-tau, but this is a pathology interaction rather than the main clathrin/SNARE adaptor role PMID:23589030.
• Nuclear/transcription/PIMREG/CATS annotations are retained as non-core or over-annotation where generic, because nuclear localization is context-specific and the main evidence frames CATS/PIMREG as changing CALM localization in leukemia-fusion biology PMID:16491119.
• Generic protein binding and high-throughput cadherin binding annotations are over-annotated; specific binding terms for clathrin, clathrin heavy chain, SNAREs, PIP2/phosphatidylinositol, and LRP1-related cargo context are more informative.

2026-06-20 second-pass audit

The second-pass audit confirmed the existing PICALM review and manual reference metadata. No annotation action changes were needed: PICALM remains curated as an ANTH-domain clathrin/SNARE cargo adaptor for clathrin-mediated endocytosis, with Alzheimer-relevant amyloid-beta/LRP1 trafficking, iron-homeostasis, tau, and nuclear-fusion contexts retained as non-core or over-annotated when they do not describe the core adaptor mechanism.