Orexin A (HCRT) Antibody – Mouse Monoclonal

This gene encodes a hypothalamic neuropeptide precursor protein that gives rise to two mature neuropeptides, orexin A and orexin B, by proteolytic processing. Orexin A and orexin B, which bind to orphan G-protein coupled receptors HCRTR1 and HCRTR2, function in the regulation of sleep and arousal. This neuropeptide arrangement may also play a role in feeding behavior, metabolism, and homeostasis. [provided by RefSeq, Jan 2010]

Function: Neuropeptides that play a significant role in the regulation of food intake and sleep-wakefulness, possibly by coordinating the complex behavioral and physiologic responses of these complementary homeostatic functions. A broader role in the homeostatic regulation of energy metabolism, autonomic function, hormonal balance and the regulation of body fluids, is also suggested. Orexin-A binds to both OX1R and OX2R with a high affinity, whereas orexin-B binds only to OX2R with a similar high affinity.

Subcellular location: Rough endoplasmic reticulum

By similarity. Cytoplasmic vesicle

By similarity. Cell junction › synapse

By similarity. Note: Associated with perikaryal rough endoplasmic reticulum as well as cytoplasmic large granular vesicles at synapses

By similarity.

Tissue specificity: Abundantly expressed in subthalamic nucleus but undetectable in other brain regions tested (hypothalamus was not tested) and in heart, placenta, lung, liver, skeletal muscle, kidney and pancreas.

Post-translational modification: Specific enzymatic cleavages at paired basic residues yield the different active peptides.

Involvement in disease: Narcolepsy 1 (NRCLP1) [MIM:161400]: Neurological disabling sleep disorder, characterized by excessive daytime sleepiness, sleep fragmentation, symptoms of abnormal rapid-eye-movement (REM) sleep, cataplexy, hypnagogic hallucinations, and sleep paralysis. Cataplexy is a sudden loss of muscle tone triggered by emotions, which is the most valuable clinical feature used to diagnose narcolepsy. Human narcolepsy is primarily a sporadically occurring disorder but familial clustering has been observed.Note: The disease is caused by mutations affecting the gene represented in this entry. Human narcolepsy is associated with a deficient orexin system. Orexins are absent and/or greatly diminished in the brain and cerebrospinal fluid (CSF) of most narcoleptic patients. Ref.9

Sequence similarities: Belongs to the orexin family.