Neurophysin II
| arginine vasopressin (neurophysin II, antidiuretic hormone, diabetes insipidus, neurohypophyseal) | |||||||
|---|---|---|---|---|---|---|---|
 neurophysin II, Bos taurus | |||||||
| Identifiers | |||||||
| Symbol | AVP | ||||||
| Alt. symbols | ARVP | ||||||
| NCBI gene | 551 | ||||||
| HGNC | 894 | ||||||
| OMIM | 192340 | ||||||
| RefSeq | NM_000490 | ||||||
| UniProt | P01185 | ||||||
| Other data | |||||||
| Locus | Chr. 20 p13 | ||||||
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Neurophysin II is a carrier protein that in humans is encoded by the AVP gene.[1] Neurophysin II is synthesized in hypothalamic magnocellular neurons as a large pre-prohormone known as prepro-vasopressin-neurophysin II, which is then cleaved and processed in the endoplasmic reticulum to form the active hormone vasopressin, neurophysin II, and copeptin.[1] Neurophysin II is packaged and transported in vesicles with vasopressin along axons, from magnocellular neurons of the hypothalamus to the posterior lobe of the pituitary.[2] Neurophysin II protects vasopressin from early breakdown by enzymes while inside the transport vesicles,[2][3] and is released into the bloodstream along with vasopressin to stimulate water reabsorption in response to an elevation of plasma osmolality, a 25% loss of blood volume, or stress.[4]
Function
[edit]Neurophysin II is a carrier protein for vasopressin (ADH). It is produced in the cell bodies of the paraventricular and supraoptic nuclei and transported to its site of release in the axon terminals of the posterior pituitary. Oxytocin, a hormone similar in structure to vasopressin, is analogously bound and transported by neurophysin I. Both hormones are nine residues long, and only differ by the amino acids at positions three and eight. Oxytocin possesses Ile-3 whereas vasopressin possesses Phe-3. Both Ile and Phe are hydrophobic amino acids and undergo analogous binding to neurophysins.
Structure
[edit]Neurophysin II is a dimer with each monomer consisting of two anti-parallel β-sheets. Each chain is identical with the exception of a single amino acid substitution (Chain 1 contains Lys-18, whereas chain 2 contains Ala-18). Each chain is 95 amino acids in length and binds a single oxytocin molecule. The amino acid sequence of Neurophysin II is:
NH2 - Ala - Met - Ser - Asp - Leu - Glu - Leu - Arg - Gln - Cys - Leu - Pro - Cys - Gly - Pro - Gly - Gly - Lys - Gly - Arg - Cys - Phe - Gly - Pro - Ser - Ile - Cys - Cys - Ala - Asp - 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 - Ala - Phe - Gly - Val - Cys - Cys - Asn - Asp - Glu - Ser - Cys - Val - Thr - Glu - Pro - Glu - Cys - Arg - Glu - Gly - Phe - His - Arg - Arg - Ala - OH
(Disulfide - bridge: - 10-54; - 13-27; - 21-44; - 28-34; - 61-73; - 67-85; - 74-79)
Clinical significance
[edit]Point mutations in the genes that encode arginine vasopressin and or its carrier protein neurophysin II underlie most cases of the familial, autosomal dominant disorder neurohypophyseal diabetes insipidus[5] (also called hereditary hypothalamic diabetes insipidus). This condition results from insufficient ADH release into systemic circulation.
See also
[edit]References
[edit]- 1 2 Watts, Jason A.; Arroyo, Juan Pablo (2023). "Rethinking Vasopressin: New Insights into Vasopressin Signaling and Its Implications". Kidney360. 4 (8): 1174–1180. doi:10.34067/KID.0000000000000194. ISSN 2641-7650. PMC 10476687. PMID 37357355.
- 1 2 Bichet, D. G. (2011). "Chapter 8 - The Posterior Pituitary." The Pituitary (Third Edition), Academic Press, p. 261-299. ISBN 9780123809261 DOI: https://doi.org/10.1016/B978-0-12-380926-1.10008-2.
- ↑ "UniProt". UniProt. Retrieved 2026-09-30.
- ↑ Hammond, P., et al. (1993). "6 - Paraendocrine Syndromes." Surgical Endocrinology, Butterworth-Heinemann, p. 59-70. ISBN 9780750613903 DOI: https://doi.org/10.1016/B978-0-7506-1390-3.50011-8.
- ↑ Christensen JH, Siggaard C, Corydon TJ, et al. (January 2004). "Six novel mutations in the arginine vasopressin gene in 15 kindreds with autosomal dominant familial neurohypophyseal diabetes insipidus give further insight into the pathogenesis". Eur. J. Hum. Genet. 12 (1): 44–51. doi:10.1038/sj.ejhg.5201086. PMID 14673472.
External links
[edit]- Neurophysin+II at the U.S. National Library of Medicine Medical Subject Headings (MeSH)