Neurophysin I

OXT
Identifiers
Aliases	OXT, OT, OT-NPI, OXT-NPI, oxytocin/neurophysin I prepropeptide
External IDs	OMIM: 167050 HomoloGene: 55494 GeneCards: OXT
Gene ontology Molecular function • oxytocin receptor binding • hormone activity • neurohypophyseal hormone activity • neuropeptide hormone activity Cellular component • terminal bouton • extracellular region • cytoplasm • extracellular space • secretory granule Biological process • response to amphetamine • regulation of digestive system process • sperm ejaculation • positive regulation of hindgut contraction • female pregnancy • positive regulation of penile erection • response to steroid hormone • signal transduction • response to activity • regulation of heart rate • response to sucrose • positive regulation of ossification • positive regulation of synapse assembly • drinking behavior • hyperosmotic salinity response • male mating behavior • positive regulation of cytosolic calcium ion concentration • response to estradiol • regulation of sensory perception of pain • response to cAMP • response to cocaine • response to progesterone • positive regulation of blood pressure • heart development • negative regulation of urine volume • response to organic cyclic compound • negative regulation of gastric acid secretion • positive regulation of prostaglandin secretion • response to peptide hormone • maternal behavior • negative regulation of blood pressure • memory • positive regulation of norepinephrine secretion • social behavior • response to glucocorticoid • grooming behavior • response to prostaglandin E • eating behavior • response to ether • positive regulation of female receptivity • sleep • maternal aggressive behavior • positive regulation of synaptic transmission • response to electrical stimulus • positive regulation of uterine smooth muscle contraction • response to food • response to retinoic acid • positive regulation of renal sodium excretion Sources:Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	5020	n/a
Ensembl	ENSG00000101405	n/a
UniProt	P01178	n/a
RefSeq (mRNA)	NM_000915	n/a
RefSeq (protein)	NP_000906.1	n/a
Location (UCSC)	Chr 20: 3.07 – 3.07 Mb	n/a
PubMed search	[1]	n/a
Wikidata

View/Edit Human

Neurophysin I is a carrier protein with a size of 10 KDa and containing 90 to 97 aminoacids that is a cleavage product (formed by splitting of a compound molecule into a simpler one) of preprooxyphysin.^[2] It is a neurohypophysial hormone that is transported in vesicles with oxytocin, the other cleavage product, along axons, from magnocellular neurons of the hypothalamus to the posterior lobe of the pituitary. Although it is stored in secretory vesicles with oxytocin and released with oxytocin, its biological action is unclear.

Structure

The amino acid sequence of Neurophysin I is:

NH₂ - Ala - Ala - Pro - Asp - Leu - Asp - Val - Arg - Lys - Cys - Leu - Pro - Cys - Gly - Pro - Gly - Gly - Lys - Gly - Arg - Cys - Phe - Gly - Pro - Asn - Ile - Cys - Cys - Ala - Glu - Glu - Leu - Gly - Cys - Phe - Val - Gly - Thr - Ala - Glu - Ala - Leu - Arg - Cys - Gln - Glu - Glu - Asn - Tyr - Leu - Pro - Ser - Pro - Cys - Gln - Ser - Gly - Gln - Lys - Ala - Cys - Gly - Ser - Gly - Gly - Arg - Cys - Ala - Val - Leu - Gly - Leu - Cys - Cys - Ser - Pro - Asp - Gly - Cys - His - Ala - Asp - Pro - Ala - Cys - Asp - Ala - Glu - Ala - Thr - Phe - Ser - Gln – Arg - OH

(Disulfide bridge: 10-54; 13-27; 21-44; 28-34; 61-73; 67-85; 74-79)

Function

Neurophysins are carrier proteins for oxytocin and vasopressin (ADH). Oxytocin and vasopressin are carried by unique neurophysins from their site of production in the cell bodies of the paraventricular and supraoptic nuclei to their site of release in the axon terminals of the posterior pituitary.

References

1. "Human PubMed Reference:".
2. Rao VV, Löffler C, Battey J, Hansmann I (1992). "The human gene for oxytocin-neurophysin I (OXT) is physically mapped to chromosome 20p13 by in situ hybridization". Cytogenet. Cell Genet. 61 (4): 271–3. doi:10.1159/000133420. PMID 1486803.