PNKD

Probable hydrolase PNKD also known as paroxysmal nonkinesiogenic dyskinesia (PNKD) is a is_associated_with::protein that in humans is encoded by the PNKD is_associated_with::gene. is_associated_with::Alternative splicing results in the transcription of three isoforms. The mouse ortholog is called brain protein 17 (Brp17).

Function
The function of PNKD proteins are unknown but the long and medium isoforms of PNKD contain a conserved β-lactamase domain which suggest it may function as an is_associated_with::enzyme. The closest mammalian homolog to PNKD is is_associated_with::HAGH, an enzyme involves in a two-step reaction to hydrolyze SLG and produce D-lactic acid and reduced GSH. However, the hydrolytic activity of PNKD is minimal.

The long form of PNKD is neuronal specific and encodes a synaptic protein that localizes dominantly to the pre-synaptic membrane. Post-synaptic area and vesicular structure also occasionally has PNKD long form. PNKD long form interacts with pre-synaptic protein RIM and inhibits synaptic exocytosis.

Clinical significance
Point mutations in PNKD exon 1 cause an inherited neurological movement disorder in human, paroxysmal non-kinesigenic dyskinesia.