Enzyme-linked receptor
An enzyme-linked receptor, also known as a catalytic receptor, is a
enzymatic activity on the intracellular side.[1] Hence a catalytic receptor is an integral membrane protein possessing both catalytic, and receptor functions.[2]
They have two important domains, an extra-cellular ligand binding domain and an intracellular domain, which has a catalytic function; and a single
transmembrane helix
. The signaling molecule binds to the receptor on the outside of the cell and causes a conformational change on the catalytic function located on the receptor inside the cell.
Examples of the enzymatic activity include:
- Receptor tyrosine kinase, as in fibroblast growth factor receptor. Most enzyme-linked receptors are of this type.[3]
- Serine/threonine-specific protein kinase, as in bone morphogenetic protein
- atrial natriuretic factor receptor
Types
The following is a list of the five major families of catalytic receptors:
| Family | Member | Gene | Catalytic activity | Endogenous ligands | Synthetic ligands |
|---|---|---|---|---|---|
| Erb[4] | ErbB1 (epidermal growth factor receptor) | EGFR | tyrosine kinase EC 2.7.10.1 | Epidermal growth factor, amphiregulin, betacellulin, epigen, epiregulin, HB-EGF, TGFa | GW583340, gefitinib, erlotinib, tyrphostins AG879 and AG1478 |
ErbB2
|
ERBB2 | " | |||
| ErbB3 | ERBB3 | " | NRG-2
|
GW583340, gefitinib, erlotinib, tyrphostins AG879 and AG1478 | |
ErbB4
|
ERBB4 | " | Betacellulin, epiregulin, HB-EGF, NRG-1, NRG-2, NRG-3, NRG-4 | GW583340, gefitinib, erlotinib, tyrphostins AG879 and AG1478 | |
GDNF (glial cell-derived neurotrophic factor)[5]
|
GFRa1 | GFRa1 | " | ||
| GFRa2 | GFRa2 | " | Neurturin > GDNF | ||
| GFRa3 | GFRa3 | " | Artemin | ||
| GFRa4 | GFRa4 | " | Persephin | ||
| NPR ( natriuretic peptide receptor)[6]
|
NPR1 | NPR1 | Atrial natriuretic peptide | ||
| NPR2 | NPR2 | " | C-type natriuretic peptide
|
||
| NPR3 | NPR3 | " | Atrial natriuretic peptide | ||
| NPR4 | NPR4 | " | Uroguanylin | ||
| trk neurotrophin receptor[7] | TrkA
|
NTRK1 | tyrosine kinase EC 2.7.10.1 | NT-3
|
GW441756, tyrphostin AG879 |
TrkB
|
NTRK2 | " | NT-3
|
||
TrkC
|
NTRK3 | " | NT-3
|
||
p75
|
NGFR | " | NGF, BDNF, NT3, NT4/5 | ||
| Toll-like[8] | TLR1
|
TLR1 | " | ||
TLR2
|
TLR2 | " | Peptidoglycan | ||
TLR3
|
TLR3 | " | polyIC, polyinosine-polycytosine | ||
TLR4
|
TLR4 | " | LPS, lipopolysaccharide derived from Gram-negative bacteria | ||
TLR5
|
TLR5 | " | Flagellin | ||
TLR6
|
TLR6 | " | |||
TLR7
|
TLR7 | " | resiquimod, imiquimod | ||
TLR8
|
TLR8 | " | |||
TLR9
|
TLR9 | " | CpG, DNA enriched in cytosine:guanosine pairs | ||
TLR10
|
TLR10 | " |
References
- ISBN 978-0-7817-6887-0. Retrieved 16 December 2010.
- PMC 2013840.
- ^ "lecture10". Archived from the original on 2007-05-25. Retrieved 2007-03-03.
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