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Gene Review

SFTPA1  -  surfactant protein A1

Bos taurus

Synonyms: PSAP, PSP-A, SFTPA1B, SP-A
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Disease relevance of SP-A


High impact information on SP-A

  • Surfactant protein A (SP-A) is crucial for lung function, including tubular myelin formation and lipid uptake by type II pneumocytes [4].
  • A recombinant carbohydrate recognition domain (CRD) of human SP-A inhibits the binding of human SP-A to galactosyl ceramide and to galactose- and mannose-bovine serum albumin, indicating that the CRD is directly involved in the binding of SP-A to these ligands [5].
  • Surfactant-associated protein-A (SP-A) is a component of pulmonary surfactant that acts as a cytokine through interaction with a cell-surface receptor (SPAR) on lung epithelial cells [6].
  • Phosphorylation of IkappaB was minimally affected by SP-A as was NFkappaB gel shift activity [6].
  • SP-A regulates important physiological processes including surfactant secretion, gene expression, and protection against apoptosis [6].

Biological context of SP-A


Anatomical context of SP-A

  • Human SP-A, unlabeled or labeled with gold particles, was bound to freshly isolated macrophages and analyzed with ELISA or the transmission electron microscope [8].
  • We concluded that SP-A is important for maintaining LA forms during surface-area cycling by stabilizing tubular myelin and multilamellar structures [11].
  • We suggest that the action of SP-A on PHA-stimulated human PBMC may involve the blocking of a costimulatory signal crucial for in vitro T-cell activation [12].
  • We have found that SP-A octadecamers exist in an "opened-bouquet" conformation in the absence of cations and interact with lipid membranes via one or two globular headgroups [13].
  • There was little degradation of SP-A by HeLa cells [14].

Associations of SP-A with chemical compounds

  • Purified PG (5% wt/wt) restored nearly normal dynamic properties to (DAPL + SP-B/C + SP-A + NL), whereas phosphatidylcholine (PC) (5% wt/wt) had no beneficial effect [15].
  • From the fractionated and blotted proteins of the receptor preparation two proteins bound SP-A in a Ca2+-dependent manner, a 40-kDa protein showing mannose dependency and a 210-kDa protein, showing no mannose sensitivity [8].
  • SP-A accelerated lipid adsorption but suppressed the final level of cholesterol in the surface [16].
  • The effects of surfactant-associated protein A (SP-A) on lipid adsorption to the air-water interface and accumulation of dipalmitoylphosphatidylcholine (DPPC) in the surface region were investigated at 37 degrees C. Dispersions used were bovine pulmonary lipid extract surfactant with or without neutral lipid (NL) [17].
  • The major surfactant protein, a 30-36-kDa class of glycoprotein (SP-A), has been isolated from bovine lung lavage and purified by affinity chromatography [18].

Physical interactions of SP-A


Regulatory relationships of SP-A

  • We studied whether antioxidant-surfactant liposomes increase cellular antioxidant activity in alveolar type II cells and whether this effect is influenced by the presence of surfactant protein A (SP-A) [20].

Other interactions of SP-A

  • However, the augmentation of aggregation of the lung lamellar bodies by annexin IV was attenuated when the lamellar bodies were preincubated with polyclonal anti-SP-A antibodies [19].

Analytical, diagnostic and therapeutic context of SP-A

  • For isolation of SP-A receptors with homologous SP-A as ligand we isolated SP-A from bovine lung lavage [8].
  • SDS-PAGE analysis of the purified SP-A showed a protein of 32-36 kDa [8].
  • We have examined the effects of surfactant-associated protein A (SP-A) purified from bovine lavage material on the surface activity of lipid extract surfactant (LES), an organic extract of pulmonary surfactant containing all of the phospholipids and SP-B and SP-C, but lacking SP-A [21].
  • The purification procedure yielded 206 mg of high-purity SP-A/kg of porcine lung, as judged by gel filtration, SDS/PAGE and Western blotting [22].
  • Gel-filtration experiments confirmed the molecular mass of SP-A in 10 mM NaCl solution [22].


  1. Physiological and inflammatory response to instillation of an oxidized surfactant in a rat model of surfactant deficiency. Bailey, T.C., Da Silva, K.A., Lewis, J.F., Rodriguez-Capote, K., Possmayer, F., Veldhuizen, R.A. J. Appl. Physiol. (2004) [Pubmed]
  2. Host defence capacities of pulmonary surfactant: evidence for 'non-surfactant' functions of the surfactant system. Pison, U., Max, M., Neuendank, A., Weissbach, S., Pietschmann, S. Eur. J. Clin. Invest. (1994) [Pubmed]
  3. Effects of early surfactant treatment persisting for one week after lung transplantation in rats. Erasmus, M.E., Hofstede, G.J., Petersen, A.H., Haagsman, H.P., Oetomo, S.B., Prop, J. Am. J. Respir. Crit. Care Med. (1997) [Pubmed]
  4. Reversible calcium-dependent interaction of liposomes with pulmonary surfactant protein A. Analysis by resonant mirror technique and near-infrared light scattering. Meyboom, A., Maretzki, D., Stevens, P.A., Hofmann, K.P. J. Biol. Chem. (1997) [Pubmed]
  5. Specificity of lung surfactant protein SP-A for both the carbohydrate and the lipid moieties of certain neutral glycolipids. Childs, R.A., Wright, J.R., Ross, G.F., Yuen, C.T., Lawson, A.M., Chai, W., Drickamer, K., Feizi, T. J. Biol. Chem. (1992) [Pubmed]
  6. Survival signaling in type II pneumocytes activated by surfactant protein-A. White, M.K., Strayer, D.S. Exp. Cell Res. (2002) [Pubmed]
  7. Assignment of the surfactant protein A gene (SFTPA) to bovine chromosome 28q1.8-->q1.9 by radiation hybrid mapping. Gjerstorff, M., Dueholm, B., Bendixen, C., Holmskov, U., Hansen, S. Cytogenet. Genome Res. (2004) [Pubmed]
  8. SP-A binding sites on bovine alveolar macrophages. Plaga, S., Plattner, H., Schlepper-Schaefer, J. Exp. Cell Res. (1998) [Pubmed]
  9. Inhibition of lung calcium-independent phospholipase A2 by surfactant protein A. Fisher, A.B., Dodia, C., Chander, A. Am. J. Physiol. (1994) [Pubmed]
  10. Inhibition of Trimeresurus flavoviridis phospholipase A2 by lung surfactant protein A (SP-A). Fisher, A.B., Dodia, C., Chander, A., Beers, M.F., Bates, S.R. Biochim. Biophys. Acta (1994) [Pubmed]
  11. Surfactant-associated protein A is important for maintaining surfactant large-aggregate forms during surface-area cycling. Veldhuizen, R.A., Yao, L.J., Hearn, S.A., Possmayer, F., Lewis, J.F. Biochem. J. (1996) [Pubmed]
  12. Surfactant associated protein-A inhibits human lymphocyte proliferation and IL-2 production. Borron, P., Veldhuizen, R.A., Lewis, J.F., Possmayer, F., Caveney, A., Inchley, K., McFadden, R.G., Fraher, L.J. Am. J. Respir. Cell Mol. Biol. (1996) [Pubmed]
  13. Structural changes of surfactant protein A induced by cations reorient the protein on lipid bilayers. Palaniyar, N., Ridsdale, R.A., Holterman, C.E., Inchley, K., Possmayer, F., Harauz, G. J. Struct. Biol. (1998) [Pubmed]
  14. Surfactant protein A is degraded by alveolar macrophages. Bates, S.R., Fisher, A.B. Am. J. Physiol. (1996) [Pubmed]
  15. Pivotal role of anionic phospholipids in determining dynamic behavior of lung surfactant. Ingenito, E.P., Mora, R., Mark, L. Am. J. Respir. Crit. Care Med. (2000) [Pubmed]
  16. Dipalmitoylphosphatidylcholine and cholesterol in monolayers spread from adsorbed films of pulmonary surfactant. Yu, S.H., Possmayer, F. J. Lipid Res. (2001) [Pubmed]
  17. Effect of pulmonary surfactant protein A and neutral lipid on accretion and organization of dipalmitoylphosphatidylcholine in surface films. Yu, S.H., Possmayer, F. J. Lipid Res. (1996) [Pubmed]
  18. Fourier-transform infrared spectroscopy studies of lipid/protein interaction in pulmonary surfactant. Reilly, K.E., Mautone, A.J., Mendelsohn, R. Biochemistry (1989) [Pubmed]
  19. Ca(2+)-dependent binding of annexin IV to surfactant protein A and lamellar bodies in alveolar type II cells. Sohma, H., Matsushima, N., Watanabe, T., Hattori, A., Kuroki, Y., Akino, T. Biochem. J. (1995) [Pubmed]
  20. Uptake of antioxidants in surfactant liposomes by cultured alveolar type II cells is enhanced by SP-A. Walther, F.J., David-Cu, R., Supnet, M.C., Longo, M.L., Fan, B.R., Bruni, R. Am. J. Physiol. (1993) [Pubmed]
  21. Pulmonary surfactant-associated protein A enhances the surface activity of lipid extract surfactant and reverses inhibition by blood proteins in vitro. Cockshutt, A.M., Weitz, J., Possmayer, F. Biochemistry (1990) [Pubmed]
  22. Pulmonary surfactant protein A isolation as a by-product of porcine pulmonary surfactant production. Kubrusly, F.S., Iourtov, D., Leme, E., Raw, I. Biotechnol. Appl. Biochem. (2004) [Pubmed]
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