protein
AP-3 complex subunit beta-2
Gene
AP3B2
Organism
Homo sapiens(9606)
Length
1082 aa
Mass
119,059 Da
AP3B2 encodes AP-3 complex subunit beta-2, a core component of the adaptor protein complex 3 (AP-3) that functions in protein sorting within the trans-Golgi network and endosomes (UniProt: Q13367). The AP-3 complex mediates recognition of cargo sorting signals and, in conjunction with the BLOC-1 complex, is required for targeting proteins into vesicles at neuronal cell bodies for delivery to neurites and nerve terminals, implicating it in synaptic function.
AP3B2 is associated with developmental and epileptic encephalopathy 48 (DEE48; MIM 617276), an autosomal recessive early-onset epilepsy characterized by seizures, global developmental delay, intellectual disability, and severe neurodevelopmental impairment (UniProt: Q13367). The protein's role in neuronal vesicle transport and lysosomal-related organelle biogenesis underscores its importance in neuronal homeostasis.
In Alzheimer's disease, AP3B2 is downregulated in post-mortem human brain tissue compared to age-matched controls (mean log2FC −1.64) as measured by TMT-labeled proteomics across subcellular fractions (Chaparral AD proteomics). This reduction in AP-3 subunit levels may impair vesicular trafficking and lysosomal protein sorting, processes implicated in amyloid-β and tau accumulation and clearance in AD pathogenesis.
Generated from the curated entity record below. May contain errors — verify against source links.
Proteomics Evidence · AD
↓ Down in ADP3
not detected
P2
not detected
S2
-1.644
S3
not detected
Mean log₂FC across detected fractions: -1.6439 (1 of 4 fractions detected)
Human post-mortem AD brain vs age-matched controls, TMT-labeled, 4 subcellular fractions (P2, P3, S2, S3), DDA proteomics.
Related Publications
Browse all →Tau molecular diversity contributes to clinical heterogeneity in Alzheimer's disease.
Dujardin Simon et al.Nature medicine2020PMID 32572268Deep Multilayer Brain Proteomics Identifies Molecular Networks in Alzheimer's Disease Progression.
Bai Bing et al.Neuron2020PMID 31926610A Multi-network Approach Identifies Protein-Specific Co-expression in Asymptomatic and Symptomatic Alzheimer's Disease.
Seyfried Nicholas T et al.Cell systems2017PMID 27989508Large-scale deep multi-layer analysis of Alzheimer's disease brain reveals strong proteomic disease-related changes not observed at the RNA level.
Johnson Erik C B et al.Nature neuroscience2022PMID 35115731Organization and regulation of gene transcription.
Cramer PatrickNature2019PMID 31462772
Function
Subunit of non-clathrin- and clathrin-associated adaptor protein complex 3 (AP-3) that plays a role in protein sorting in the late-Golgi/trans-Golgi network (TGN) and/or endosomes. The AP complexes mediate both the recruitment of clathrin to membranes and the recognition of sorting signals within the cytosolic tails of transmembrane cargo molecules. AP-3 appears to be involved in the sorting of a subset of transmembrane proteins targeted to lysosomes and lysosome-related organelles. In concert with the BLOC-1 complex, AP-3 is required to target cargos into vesicles assembled at cell bodies for delivery into neurites and nerve terminals
Disease associations
Developmental and epileptic encephalopathy 48DEE48
A form of epileptic encephalopathy, a heterogeneous group of severe early-onset epilepsies characterized by refractory seizures, neurodevelopmental impairment, and poor prognosis. Development is normal prior to seizure onset, after which cognitive and motor delays become apparent. DEE48 is an autosomal recessive form characterized by onset of seizures in the first year of life. Affected individuals manifest global developmental delay, intellectual disability, absent speech, and poor, if any, motor development.
Sources
Last updated 5/8/2026, 6:32:21 AM