Secretoglobin | |||||||||
---|---|---|---|---|---|---|---|---|---|
Identifiers | |||||||||
Symbol | Secretoglobin | ||||||||
Pfam | PF01099 | ||||||||
InterPro | IPR016126 | ||||||||
PROSITE | PS51311 | ||||||||
SCOP2 | d1utra_ / SCOPe / SUPFAM | ||||||||
CDD | cd00633 | ||||||||
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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.
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.
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 | ||||||
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 protein built from three lipophilin-like genes in groups 2 and 3. [3]
Subfamilies 4 through 6 are not found in human or mice, and they might as well be duplicates of existing groups. [3]
Subfamily 6 was supposed to include rat RYD5, [3] now reassigned Scgb1c1. [4]
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]
Fel d 1 was supposed to be split 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, possibly invalidating subfamilies 4 and 5 as well. [6]
Vitronectin is a glycoprotein of the hemopexin family which is abundantly found in serum, the extracellular matrix and bone. In humans it is encoded by the VTN gene.
Fel d 1 is a secretoglobin protein complex that, in cats, is encoded by the CH1 and CH2 genes.
Uteroglobin, also known as secretoglobin family 1A member 1 (SCGB1A1), is a protein that in humans is encoded by the SCGB1A1 gene.
The lipocalins are a family of proteins which transport small hydrophobic molecules such as steroids, bilins, retinoids, and lipids and most lipocalins are also able to bind to complexed iron as well as heme. They share limited regions of sequence homology and a common tertiary structure architecture. This is an eight stranded antiparallel beta barrel with a repeated + 1 topology enclosing an internal ligand binding site.
The transforming growth factor beta (TGF-β) family is a large group of structurally related cell regulatory proteins that was named after its first member, TGF-β1, originally described in 1983. They interact with TGF-beta receptors.
Cadherin EGF LAG seven-pass G-type receptor 1 also known as flamingo homolog 2 or cadherin family member 9 is a protein that in humans is encoded by the CELSR1 gene.
Vitamin D-binding protein (DBP), also/originally known as gc-globulin, is a protein that in humans is encoded by the GC gene.
Microsomal triglyceride transfer protein large subunit is a protein that in humans is encoded by the MTTP gene.
Collagen alpha-1(VI) chain is a protein that in humans is encoded by the COL6A1 gene.
Interleukin-12 receptor, beta 1, or IL-12Rβ1 in short, is a subunit of the interleukin 12 receptor. IL12RB1, is the name of its human gene. IL-12Rβ1 is also known as CD212.
ATP-binding cassette sub-family A member 2 is a protein that in humans is encoded by the ABCA2 gene.
ATP-binding cassette sub-family B member 9 is a protein that in humans is encoded by the ABCB9 gene.
ATP-binding cassette sub-family A member 3 is a protein that in humans is encoded by the ABCA3 gene.
Striated muscle preferentially expressed protein kinase, in the human is encoded by the SPEG gene, a member of the myosin light chain kinase protein family. SPEG is involved in the development of the muscle cell cytoskeleton, and the expression of this gene has important roles in the development of skeletal muscles, and their maintenance and function. Mutations are associated with centronuclear myopathies a group of congenital disorders where the cell nuclei are abnormally centrally placed.
ATP-binding cassette sub-family G member 4 is a protein that in humans is encoded by the ABCG4 gene.
Secretoglobin family 1D member 2 is a protein that in humans is encoded by the SCGB1D2 gene.
ATP-binding cassette sub-family B member 8, mitochondrial is a protein that in humans is encoded by the ABCB8 gene.
The insulin/IGF/relaxin family is a group of evolutionary related proteins which possess a variety of hormonal activities. Family members in human include two subfamilies:
Major urinary proteins (Mups), also known as α2u-globulins, are a subfamily of proteins found in abundance in the urine and other secretions of many animals. Mups provide a small range of identifying information about the donor animal, when detected by the vomeronasal organ of the receiving animal. They belong to a larger family of proteins known as lipocalins. Mups are encoded by a cluster of genes, located adjacent to each other on a single stretch of DNA, that varies greatly in number between species: from at least 21 functional genes in mice to none in humans. Mup proteins form a characteristic glove shape, encompassing a ligand-binding pocket that accommodates specific small organic chemicals.
Phosphatidylcholine transfer protein (PCTP) also known as StAR-related lipid transfer domain protein 2 (STARD2) is a specific intracellular phospholipid binding protein that can transfer phosphatidylcholine between different membranes in the cytosol.