ATN1

Dentatorubral pallidoluysian atrophy (DRPLA) is a rare neurodegenerative disorder characterized by cerebellar ataxia, myoclonic epilepsy, choreoathetosis, and dementia. The disorder is related to the expansion from 7-35 copies to 49-93 copies of a trinucleotide repeat (CAG/CAA) within this gene. The encoded protein includes a serine repeat and a region of alternating acidic and basic amino acids, as well as the variable glutamine repeat. Alternative splicing results in two transcripts variants that encode the same protein. [provided by RefSeq, Jul 2016]

Full Name

Atrophin 1

Function

Transcriptional corepressor. Recruits NR2E1 to repress transcription. Promotes vascular smooth cell (VSMC) migration and orientation (By similarity).
Corepressor of MTG8 transcriptional repression. Has some intrinsic repression activity which is independent of the number of poly-Gln (polyQ) repeats.

Biological Process

Central nervous system development Source: ProtInc
Negative regulation of transcription by RNA polymerase II Source: UniProtKB
Neuron apoptotic process Source: UniProtKB

Cellular Location

Nucleus; Perinuclear region; Cell junction. Shuttles between nucleus and cytoplasm. Colocalizes with FAT1 in the perinuclear area, at cell-cell junctions and leading edges of cells (By similarity). Colocalizes with MTG8 in discrete nuclear dots. Proteolytic fragment F1 appears to remain in nucleus. Fragment F2 is exported into the cytoplasm. Fragment F2 from mutant sequences with longer poly-Gln (polyQ) tracts are additionally located to the cytoplasmic membrane and to certain organelles.

Involvement in disease

Dentatorubral-pallidoluysian atrophy (DRPLA): Autosomal dominant neurodegenerative disorder characterized by a loss of neurons in the dentate nucleus, rubrum, glogus pallidus and Luys'body. Clinical features are myoclonus epilepsy, dementia, and cerebellar ataxia. Onset of the disease occurs usually in the second decade of life and death in the fourth.
Congenital hypotonia, epilepsy, developmental delay, and digital anomalies (CHEDDA): An autosomal dominant neurodevelopmental syndrome characterized by severe global developmental delay, impaired intellectual development, poor or absent language, significant motor disability with inability to walk, dysmorphic facial features, skeletal anomalies, and variable congenital malformations. Most patients also have seizures and structural brain abnormalities.

PTM

Phosphorylated in vitro by MAPK8/JNK1 on Ser-739. Mutant ATN1 sequences with expanded poly-Gln (polyQ) traits are more slowly phosphorylated.
Proteolytically cleaved, probably in the nucleus, to produce two C-terminal fragments of 140 kDa (F1) and 125 kDa (F2) each containing poly-Gln (polyQ) tracts. F2 is produced by cleavage by caspases and is exported into the cytoplasm. In vitro, cleavage increases with an increase in the number of polyQ tracts. C-terminal proteolytic products appear to be the cause of cell toxicity. In vitro cleavage at Asp-109.