Surfactant protein A1
protein-coding gene in the species Homo sapiens
Surfactant protein A1 (SP-A1), also known as Pulmonary surfactant-associated protein A1 (PSP-A) is a protein that in humans is encoded by the SFTPA1 gene.
SP-A1 is primarily synthesised in type II alveolar cells in the lung, as part of a complex of lipids and proteins known as pulmonary surfactant. The function of this complex is to reduce surface tension in the alveoli and prevent their collapse during expiration. The protein component of surfactant helps in the modulation of the innate immune response, and inflammatory processes.
SP-A1 is a member of a subfamily of C-type lectins called collectins. Together with SP-A2, they are the most abundant proteins of pulmonary surfactant. SP-A1 binds to the carbohydrates found in the surface of several microorganisms and helps in the defense against respiratory pathogens.
Surfactant homeostasis is critical for breathing (and thus survival) in the prematurely born infant, but also for maintaining lung health, and normal lung function throughout life. Changes in the amount or composition of surfactant can alter its function and are associated with respiratory diseases.
Gene
SFTPA1 is located in the long arm q of chromosome 10, close to SFTPA2.
Begin with the source’s own compact description: “Surfactant protein A1” is protein-coding gene in the species Homo sapiens. The dossier treats that line as a proposition to test through Surfactant, protein and protein-coding, not as a finished interpretation.
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The date and method of observation matter as much as the stated conclusion, especially where classification or consensus has changed. The source revision retrieved here is dated Jun 15, 2026. The linked authority identifier is Q18060624.
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This entry incorporates text from “Surfactant protein A1” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.