Surfactant protein A
| surfactant, pulmonary-associated protein A1 | |
|---|---|
| Identifiers | |
| Symbol | SFTPA1 |
| Alt. symbols | SFTP1 |
| Entrez | 6435 |
| HUGO | 10798 |
| OMIM | 178630 |
| RefSeq | NM_005411 |
| UniProt | Q8IWL2 |
| Other data | |
| Locus | Chr. 10 q22.3 |
| surfactant, pulmonary-associated protein A2B | |
|---|---|
| Identifiers | |
| Symbol | SFTPA2B |
| Entrez | 6436 |
| HUGO | 10799 |
| OMIM | 178642 |
| RefSeq | NM_006926 |
| UniProt | Q8IWL1 |
| Other data | |
| Locus | Chr. 10 q22.3 |
Surfactant protein A is an innate immune system collectin. It is water-soluble and has collagen-like domains similar to SP-D. It is part of the innate immune system and is used to opsonize bacterial cells in the alveoli marking them for phagocytosis by alveolar macrophages. SP-A may also play a role in negative feedback limiting the secretion of pulmonary surfactant. SP-A is not required for pulmonary surfactant to function but does confer immune effects to the organism.[1]
During Parturition
The role of Surfactant protein A (or SP-A) in childbirth is indicated in studies with mice.[2] Mice which gestate for 19 days typically show signs of SP-A in amniotic fluid at around 16 days. If SP-A is injected into the uterus at 15 days, mice typically deliver early. Inversely, an SP-A inhibitor injection causes notable delays in birth.
The presence of Surfactant Protein A seemed to trigger an inflammatory response in the uterus of the mice, but later studies found an anti-inflammatory response in humans.[3] In fact, the level of SP-A in a human uterus typically decreases during labor.
Immune Functions
Research on SP-A has been done mainly in rodents including mice and rats. This research has shown that mice deficient in SP-A are more susceptible to infections from group B Streptoccoal organisms,[4] Pseudomonas aeruginosa,[5] and likely other organisms. The immune functions of SP-A are time, temperature, and concentration dependant.[6]
Location
SP-A is found in the pulmonary surfactant in lungs. SP-A and SP-D are also present in extrapulmonary tissues.[7]
See also
External links
- Surfactant Protein A at the US National Library of Medicine Medical Subject Headings (MeSH)
References
- ↑ Boron W, Boulpaep E. Medical Physiology. 2nd ed. Philadelphia: Elsevier; 2012.
- ↑ Condon, Jennifer C.; Jeyasuria, Pancharatnam; Faust, Julie M.; Mendelson, Carole R. (2004). "Surfactant protein secreted by the maturing mouse fetal lung acts as a hormone that signals the initiation of parturition". Proceedings of the National Academy of Sciences 101 (14): 4978–83. doi:10.1073/pnas.0401124101. JSTOR 3371804. PMC 387359. PMID 15044702.
- ↑ Lee, Deug-Chan; Romero, Roberto; Kim, Chong Jai; Chaiworapongsa, Tinnakorn; Tarca, Adi L.; Lee, JoonHo; Suh, Yeon-Lim; Mazaki-Tovi, Shali; et al. (2010). "Surfactant Protein-A as an Anti-Inflammatory Component in the Amnion: Implications for Human Pregnancy". The Journal of Immunology 184 (11): 6479–91. doi:10.4049/jimmunol.0903867. PMC 3103775. PMID 20439915.
- ↑ http://www.jimmunol.org/content/158/9/4336.short
- ↑ http://europepmc.org/abstract/MED/9761768
- ↑ http://europepmc.org/abstract/MED/2306370/
- ↑ Haagsman, HP; Diemel, RV (May 2001). "Surfactant-associated proteins: functions and structural variation". Comp Biochem Physiol A Mol Integr Physiol 129 (1): 91–108. PMID 11369536.