Ube3A Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Ube3A Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Overview
UBE3A (also known as E6-AP, encoded by the UBE3A gene) is a HECT (Homologous to E6-AP C-terminus) domain E3 ubiquitin ligase. The protein was originally identified as forming a complex with the viral E6 protein from human papillomavirus (HPV) that targets p53 for degradation <sup>[1]</sup>. In the absence of viral E6, UBE3A performs essential functions in neuronal protein homeostasis.
UBE3A is expressed in all tissues but has crucial roles in the brain due to genomic imprinting—[neurons](/entities/neurons) specifically express only the maternally-inherited allele, making them uniquely vulnerable to mutations.
Structure
UBE3A contains several key domains:
N-terminal region: Multiple low-complexity segments with putative regulatory functions
HECT domain: ~350 amino acid catalytic domain at the C-terminus
Catalytic cysteine: C820 forms thioester intermediate with ubiquitin
The HECT domain adopts a bilobal structure with an E2-binding site and a catalytic lobe.
Function
Ubiquitination Cascade
UBE3A catalyzes ubiquitination through:
Ubiquitin activation: Receives ubiquitin from E1 (UBA1)
Thioester formation: Forms Ub-C820 intermediate
Substrate ubiquitination: Transfers ubiquitin to lysine residues
Key Neuronal Substrates
UBE3A ubiquitinates several important neuronal proteins:
The study of Ube3A Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
Cross-links
UBE3A Gene
Ubiquitin-Proteasome System
Angelman Syndrome
Synaptic Plasticity
References
Mabb AM, et al, UBE3A and the ubiquitin system in synaptic function (2014)
Sell GL, et al, Targeting UBE3A for Angelman syndrome and autism (2022)