Recombinant Human AP-3 complex subunit beta-2 (AP3B2), partial

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

Subcellular Location

Cytoplasmic vesicle, clathrin-coated vesicle membrane (Peripheral membrane protein); Golgi apparatus

Disease Association

Developmental and epileptic encephalopathy 48 (DEE48) : 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. [The disease may be caused by variants affecting the gene represented in this entry]

Tissue Specificity

Isoform 1 expression is specific to nervous system. Expressed in nerve terminal and cell body, and is associated with nerve-terminal vesicles. Expression seen in Purkinje cells, cortical neurons, neuroectodermal tumors and graded in cerebral cortex (deeper layers exhibit stronger expression) (PubMed:1851215). Isoform 2 is expressed at high levels in brain and testis (PubMed:17453999)

Subunit

AP-3 associates with the BLOC-1 complex (By similarity). Adaptor protein complex 3 (AP-3) is a heterotetramer composed of two large adaptins (delta-type subunit AP3D1 and beta-type subunit AP3B1 or AP3B2), a medium adaptin (mu-type subunit AP3M1 or AP3M2) and a small adaptin (sigma-type subunit APS1 or AP3S2)

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• Chen C. et al. Characterization of AP3B2_v2, a novel splice variant of human AP3B2. — DNA Seq. (2007)
• Peden A.A. et al. Correction of beta3B. (AUG-)
• Zody M.C. et al. Analysis of the DNA sequence and duplication history of human chromosome 15. — Nature (2006)
• The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC). — Genome Res. (2004)
• Darnell R.B. et al. Antiserum from a patient with cerebellar degeneration identifies a novel protein in Purkinje cells, cortical neurons, and neuroectodermal tumors. — J. Neurosci. (1991)
• Mayya V. et al. Quantitative phosphoproteomic analysis of T cell receptor signaling reveals system-wide modulation of protein-protein interactions. — Sci. Signal. (2009)
• Assoum M. et al. Autosomal-recessive mutations in AP3B2, adaptor-related protein complex 3 beta 2 subunit, cause an early-onset epileptic encephalopathy with optic atrophy. — Am. J. Hum. Genet. (2016)