NAPSA explained

Napsin-A is an aspartic proteinase that is encoded in humans by the NAPSA gene.^[1] The name napsin comes from novel aspartic proteinase of the pepsin family.^[2]

The activation peptide of an aspartic proteinase acts as an inhibitor of the active site. These peptide segments, or pro-parts, are deemed important for correct folding, targeting, and control of the activation of aspartic proteinase zymogens. The pronapsin A gene is expressed predominantly in lung and kidney. Its translation product is predicted to be a fully functional, glycosylated aspartic proteinase precursor containing an RGD motif and an additional 18 residues at its C-terminus.^[1]

Utility

Detection of NAPSA gene expression can be used to distinguish adenocarcinomas from other forms of lung cancer.^[3]

Further reading

• Koelsch G, Mares M, Metcalf P, Fusek M . Multiple functions of pro-parts of aspartic proteinase zymogens. . FEBS Lett. . 343 . 1 . 6–10 . 1994 . 8163018 . 10.1016/0014-5793(94)80596-2 . 32345795 . free . 1994FEBSL.343....6K .
• Book: Blundell TL, Guruprasad K, Albert A, etal . Aspartic Proteinases . Adv. Exp. Med. Biol. . 436 . 1–13 . 1998 . 9561193 . 10.1007/978-1-4615-5373-1_1 . 978-1-4613-7452-7 .
• Chuman Y, Bergman A, Ueno T, etal . Napsin A, a member of the aspartic protease family, is abundantly expressed in normal lung and kidney tissue and is expressed in lung adenocarcinomas. . FEBS Lett. . 462 . 1–2 . 129–34 . 2000 . 10580105 . 10.1016/S0014-5793(99)01493-3 . 23355055 . free .
• Schauer-Vukasinovic V, Bur D, Kling D, etal . Human napsin A: expression, immunochemical detection, and tissue localization. . FEBS Lett. . 462 . 1–2 . 135–9 . 2000 . 10580106 . 10.1016/S0014-5793(99)01458-1 . 32798620 . free .
• Yan R, Bienkowski MJ, Shuck ME, etal . Membrane-anchored aspartyl protease with Alzheimer's disease beta-secretase activity. . Nature . 402 . 6761 . 533–7 . 1999 . 10591213 . 10.1038/990107 . 1999Natur.402..533Y . 4320087 .
• Cook M, Bühling F, Ansorge S, etal . Pronapsin A and B gene expression in normal and malignant human lung and mononuclear blood cells. . Biochim. Biophys. Acta . 1577 . 1 . 10–6 . 2002 . 12151090 . 10.1016/s0167-4781(02)00400-1.
• Strausberg RL, Feingold EA, Grouse LH, etal . Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences. . Proc. Natl. Acad. Sci. U.S.A. . 99 . 26 . 16899–903 . 2003 . 12477932 . 10.1073/pnas.242603899 . 139241 . 2002PNAS...9916899M . free .
• Brasch F, Ochs M, Kahne T, etal . Involvement of napsin A in the C- and N-terminal processing of surfactant protein B in type-II pneumocytes of the human lung. . J. Biol. Chem. . 278 . 49 . 49006–14 . 2004 . 13129928 . 10.1074/jbc.M306844200 . free .
• Ota T, Suzuki Y, Nishikawa T, etal . Complete sequencing and characterization of 21,243 full-length human cDNAs. . Nat. Genet. . 36 . 1 . 40–5 . 2004 . 14702039 . 10.1038/ng1285 . free .
• Innocenti M, Zucconi A, Disanza A, etal . Abi1 is essential for the formation and activation of a WAVE2 signalling complex. . Nat. Cell Biol. . 6 . 4 . 319–27 . 2004 . 15048123 . 10.1038/ncb1105 . 22767022 .

Notes and References

1. Web site: Entrez Gene: NAPSA napsin A aspartic peptidase.
2. Tatnell . Peter J . Powell . David J . Hill . Jeffrey . Smith . Trudi S . Tew . David G . Kay . John . Napsins: new human aspartic proteinases . FEBS Letters . 11 December 1998 . 441 . 1 . 43–48 . 10.1016/s0014-5793(98)01522-1 . 9877162. 27656626 .
3. Ueno T, Linder S, Elmberger G . Aspartic proteinase napsin is a useful marker for diagnosis of primary lung adenocarcinoma. . Br. J. Cancer . 88 . 8 . 1229–33 . 2004 . 10.1038/sj.bjc.6600879 . 12698189 . 2747556 .