SFTPC is a 197-residue protein made up of two halves: a unique N-terminal propeptide domain and a C-terminal BRICHOS domain. The around 100-aa long propeptide domain actually contains not only the cleaved part, but also the mature peptide. It can be further broken down into a 23-aa helical transmembrane propeptide proper, the mature secreted SP-C (24-58), and a linker (59-89) that connects to the BRICHOS domain.
The propeptide of pulmonary surfactant C has an N-terminal alpha-helical segment whose suggested function was stabilization of the protein structure, since the mature peptide can irreversibly transform from its native alpha-helical structure to beta-sheet aggregates and form amyloid fibrils. The correct intracellular trafficking of proSP-C has also been reported to depend on the propeptide.
The structure of the BRICHOS domain has been solved. Mutations in this domain also lead to amyloid fibrils made up of the mature peptide, suggesting a chaperone activity.
Pérez-Gil J (2002). "Lipid-protein interactions of hydrophobic proteins SP-B and SP-C in lung surfactant assembly and dynamics". Pediatric Pathology & Molecular Medicine. 20 (6): 445–69. doi:10.1080/15227950152625783. PMID11699574.
Solarin KO, Wang WJ, Beers MF (2002). "Synthesis and post-translational processing of surfactant protein C". Pediatric Pathology & Molecular Medicine. 20 (6): 471–500. doi:10.1080/15227950152625792. PMID11699575.
Johansson J, Curstedt T, Robertson B (2002). "Artificial surfactants based on analogues of SP-B and SP-C". Pediatric Pathology & Molecular Medicine. 20 (6): 501–18. doi:10.1080/15227950152625800. PMID11699576.
Wood S, Yaremko ML, Schertzer M, Kelemen PR, Minna J, Westbrook CA (December 1994). "Mapping of the pulmonary surfactant SP5 (SFTP2) locus to 8p21 and characterization of a microsatellite repeat marker that shows frequent loss of heterozygosity in human carcinomas". Genomics. 24 (3): 597–600. doi:10.1006/geno.1994.1673. PMID7713515.
Hatzis D, Deiter G, deMello DE, Floros J (1994). "Human surfactant protein-C: genetic homogeneity and expression in RDS; comparison with other species". Experimental Lung Research. 20 (1): 57–72. doi:10.3109/01902149409064373. PMID8181452.
Nogee LM, Dunbar AE, Wert SE, Askin F, Hamvas A, Whitsett JA (February 2001). "A mutation in the surfactant protein C gene associated with familial interstitial lung disease". The New England Journal of Medicine. 344 (8): 573–9. doi:10.1056/NEJM200102223440805. PMID11207353.