pulmonary surfactant-associated protein B; SP-B; 18 kD pulmonary-surfactant protein; 6 kD protein; pulmonary surfactant-associated proteolipid SPL(Phe) (SFTPB, SFTP3)

Function

• Pulmonary surfactant-associated proteins promote alveolar stability by lowering the surface tension at the air-liquid interface in the peripheral air spaces
• SP-B increases the collapse pressure of palmitic acid to nearly 70 millinewtons per meter

Structure

• homodimer; disulfide-linked
• contains 1 saposin A-type domain
• contains 3 saposin B-type domains

Compartment

• secreted, extracellular space, surface film

Pathology

• defects in SFTPB are the cause of pulmonary surfactant metabolism dysfunction type 1 (pulmonary alveolar proteinosis due to surfactant protein B)
• genetic variations in SFTPB are a cause of susceptibility to neonatal respiratory distress syndrome
  • a variation Ile to Thr at position 131 influences the association between specific alleles of SFTPA1 & neonatal RDS

More general terms

• secreted protein
• glycoprotein
• proteolipid

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=6439
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:6439
• OMIM: https://mirror.omim.org/entry/178640
• OMIM: https://mirror.omim.org/entry/265120
• OMIM: https://mirror.omim.org/entry/267450
• UniProt: http://www.uniprot.org/uniprot/P07988.html