Gene

Cytoplasm

Nuclear localization sequence

Cell biology

Neuroscience

Biology

UBE3A

Ubiquitin ligase

Nucleus

Ubiquitin

Gene knockin

Genetics

Angelman syndrome

Gene isoform

Nature Neuroscience

Mutations affecting the gene encoding the ubiquitin ligase UBE3A cause Angelman syndrome. Although most studies focus on the synaptic function of UBE3A, we show that UBE3A is highly enriched in the nucleus of mouse and human neurons. We found that the two major isoforms of UBE3A exhibit highly distinct nuclear versus cytoplasmic subcellular localization. Both isoforms undergo nuclear import through direct binding to PSMD4 (also known as S5A or RPN10), but the amino terminus of the cytoplasmic isoform prevents nuclear retention. Mice lacking the nuclear UBE3A isoform recapitulate the behavioral and electrophysiological phenotypes of Ube3am–/p+ mice, whereas mice harboring a targeted deletion of the cytosolic isoform are unaffected. Finally, we identified Angelman syndrome-associated UBE3A missense mutations that interfere with either nuclear targeting or nuclear retention of UBE3A. Taken together, our findings elucidate the mechanisms underlying the subcellular localization of UBE3A, and indicate that the nuclear UBE3A isoform is the most critical for the pathophysiology of Angelman syndrome. This paper elucidates the mechanism regulating the subcellular localization of UBE3A and demonstrates that abrogation of UBE3A nuclear localization leads to electrophysiological and behavioral impairments in mice and to Angelman syndrome in humans.

Loss of nuclear UBE3A causes electrophysiological and behavioral deficits in mice and is associated with Angelman syndrome