| Secretoglobin | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| Symbol | Secretoglobin | ||||||||
| Pfam | PF01099 | ||||||||
| InterPro | IPR016126 | ||||||||
| PROSITE | PS51311 | ||||||||
| SCOP2 | d1utra_ / SCOPe / SUPFAM | ||||||||
| CDD | cd00633 | ||||||||
| |||||||||
Secretoglobins (SCGBs) are a family of small, alpha-helical, disulfide linked, dimeric proteins found only in mammals. This family was formerly known as the Uteroglobin/Clara cell 10-kDa family, after the two aliases of its founding member Uteroglobin.
Structure and function
The proteins are mostly alpha-helical, and the dimer is formed in an antiparallel way. The dimer interface features a cavity formed across the two monomers, which can accommodate small to medium sized ligands like steroids and phospholipids.[1] The binding and release may be coupled with the redox state of the cystines, i.e. the presence of these disulfide bonds.[2]
Many have regulatory functions.
Classification
The family was classified by sequence homology into 6 subfamilies in 2006.[3] The human and mouse genomes only contain the first three families, per an 2011 update. Not every family is monophyletic.[4]
| Subfamily | Group | Member | |||||
|---|---|---|---|---|---|---|---|
| Symbol[4] | Name | Ligand(s) | |||||
| 1 | UGB | A | UGB | SCGB1A1 | Uteroglobin (UGB); blastokinin, CCSP | phosphatidylcholine, phosphatidylinositol, PCB | |
| B | ABPA-like | Scgb1b2 (rodent) | in general: steroid pheromones | ||||
| C | SCGB1C1 | ||||||
| SCGB1C2 | |||||||
| D | Lipophilin A/B | ||||||
| 2 | A | Mammaglobin | SCGB2A1 | Mammaglobin-B; lipophilin-C | |||
| SCGB2A2 | Mammaglobin-A | ||||||
| B | ABPBG-like | Scgb2b1 (rodent) | in general: steroid pheromones | ||||
| 3 | UGB-like | A | UGB-like | SCGB3A1 | |||
| SCGB3A2 | |||||||
Rat prostatein (rat prostatic steroid binding protein) is a three component, tetrameric protein complex built from three lipophilin-like genes in groups 2 and 3. Some sources describe it as the ortholog of lipophilin.[3]
Extra subfamilies
Subfamilies 4 and 6 were originally described as found in human and mice, but they are now treated as duplicates of existing groups. Subfamily 5 is found in neither to begin with.[3]
Subfamily 4 formerly included what is now known as group 1B and 2B as group 4A. Pairs of 1B/2B (ABP) genes are arranged head-to-head on the chromosome into "modules" that have been independently duplicated.[4]
Subfamily 6 was supposed to include human and rat RYD5,[3] now reassigned Scgb1c1.[4]
Fel d 1 was supposed to be put into two subfamilies: chain 1 in subfamily 4, and chain 2 in subfamily 5.[3] Although it is not mentioned in the 2011 update, InterPro matches suggest that CH1 is similar to 1B and CH2 is similar to 2B.[5] Extra computational research confirms the similarity, invalidating subfamilies 4 and 5 fully.[6]
References
- ↑ Umland TC, Swaminathan S, Singh G, Warty V, Furey W, Pletcher J, Sax M (August 1994). "Structure of a human Clara cell phospholipid-binding protein-ligand complex at 1.9 A resolution". Nature Structural Biology. 1 (8): 538–45. doi:10.1038/nsb0894-538. PMID 7664082. S2CID 28261246.
- ↑ Härd T, Barnes HJ, Larsson C, Gustafsson JA, Lund J (November 1995). "Solution structure of a mammalian PCB-binding protein in complex with a PCB". Nature Structural Biology. 2 (11): 983–9. doi:10.1038/nsb1195-983. PMID 7583672. S2CID 10369347.
- 1 2 3 4 5 Klug J, Beier HM, Bernard A, Chilton BS, Fleming TP, Lehrer RI, et al. (25 January 2006). "Uteroglobin/Clara cell 10-kDa family of proteins: nomenclature committee report". Annals of the New York Academy of Sciences. 923 (1): 348–54. doi:10.1111/j.1749-6632.2000.tb05549.x. PMID 11193777. S2CID 38862724.
- 1 2 3 4 Jackson BC, Thompson DC, Wright MW, McAndrews M, Bernard A, Nebert DW, Vasiliou V (October 2011). "Update of the human secretoglobin (SCGB) gene superfamily and an example of 'evolutionary bloom' of androgen-binding protein genes within the mouse Scgb gene superfamily". Human Genomics. 5 (6): 691–702. doi:10.1186/1479-7364-5-6-691. PMC 3251818. PMID 22155607.
- ↑ "Fel d 1 chain 1", Mus musculus, "Fel d 1 chain 2", Mus musculus. InterPro.
- ↑ Durairaj R, Pageat P, Bienboire-Frosini C (2018). "Another cat and mouse game: Deciphering the evolution of the SCGB superfamily and exploring the molecular similarity of major cat allergen Fel d 1 and mouse ABP using computational approaches". PLOS ONE. 13 (5): e0197618. Bibcode:2018PLoSO..1397618D. doi:10.1371/journal.pone.0197618. PMC 5957422. PMID 29771985.