Surfactant protein A1 (SFTPA1)

Surfactant protein A1 (SFTPA1) is a lung-specific, secreted protein within the collectin family of C-type lectins, mainly produced by alveolar type II epithelial cells. It plays an essential role in maintaining surfactant homeostasis by reducing surface tension at the air-liquid interface in the lung alveoli, supporting normal respiration. In addition, SFTPA1 is a soluble pattern-recognition receptor that binds to specific carbohydrate- and lipid-containing moieties on pathogens, facilitating their opsonization and clearance by immune cells, especially alveolar macrophages, and contributing to the regulation of inflammatory and immune responses in the lungs. SFTPA1 mutations and regulatory variant differences are linked to lung diseases including idiopathic pulmonary fibrosis, interstitial lung disease, pulmonary infections, and some lung cancers, where its genetic and epigenetic regulation may serve as a biomarker of disease susceptibility and progression.

Other names

COLEC4SP-A1SP-ASFTP135 kDa pulmonary surfactant-associated proteinSurfactant, pulmonary-associated protein A1APulmonary surfactant-associated protein A1Alveolar proteinosis proteinCollectin-4SFTPA1BPSP-A

Drug interactions are not well-characterized; no approved therapeutics directly target SFTPA1. Experimental modulation includes transcriptional induction or inhibition (e.g., glucocorticoids down-regulate expression).