Surfactant protein C (SP-C), is one of the pulmonary surfactant proteins. In humans this is encoded by the SFTPC gene.[5][6][7]
SFTPC | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Identifiers | |||||||||||||||||||||||||||||||||||||||||||||||||||
Aliases | SFTPC, BRICD6, PSP-C, SFTP2, SMDP2, SP-C, surfactant protein C, SP5 | ||||||||||||||||||||||||||||||||||||||||||||||||||
External IDs | OMIM: 178620 MGI: 109517 HomoloGene: 2271 GeneCards: SFTPC | ||||||||||||||||||||||||||||||||||||||||||||||||||
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It is a membrane protein.
Surfactant protein C, N terminal propeptide | |||||||||
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Identifiers | |||||||||
Symbol | SP_C-Propep | ||||||||
Pfam | PF08999 | ||||||||
InterPro | IPR001729 | ||||||||
PROSITE | PDOC00298 | ||||||||
OPM superfamily | 69 | ||||||||
OPM protein | 1spf | ||||||||
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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.[8]
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.[9]
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.[8]
Mutations are associated with surfactant metabolism dysfunction type 2.
Humans and animals born lacking SP-C tend to develop progressive interstitial lung disease.
Recombinant SP-C is used in Venticute, an artificial lung surfactant.
A process to mass-produce an analogue called rSP-C33Le by fusion with spidroin has been described.[10]