Surfactant catabolism by alveolar macrophages plays a small but critical part in surfactant recycling and metabolism. Upon ligand binding, granulocyte-macrophage colony-stimulating factor receptor (GM-CSF), a heterodimer of alpha (CSF2RA) and beta (CSF2RB) subunits, initiates a signalling process that not only induces proliferation, differentiation and functional activation of hematopoietic cells but can also determine surfactant uptake into alveolar macrophages and its degradation via clathrin-coated vesicles. Defects in human CSF2RB can cause pulmonary surfactant metabolism dysfunction 5 (SMDP5; MIM:614370, aka pulmonary alveolar proteinosis 5, PAP5), a rare lung disorder due to impaired surfactant homeostasis characterised by alveoli filling with floccular material causing respiratory failure. Mutations in CSF2RB that cause SMDP5 are R211Efs*54 and S271L (Tanaka et al. 2011, Suzuki et al. 2011).
Tanaka, T, Motoi, N, Tsuchihashi, Y, Tazawa, R, Kaneko, C, Nei, T, Yamamoto, T, Hayashi, T, Tagawa, T, Nagayasu, T, Kuribayashi, F, Ariyoshi, K, Nakata, K, Morimoto, K
Suzuki, T, Maranda, B, Sakagami, T, Catellier, P, Couture, CY, Carey, BC, Chalk, C, Trapnell, BC
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