Angiotensin II, type I receptor-associated protein
SMART accession number:
SM00805
Description:
This family consists of several angiotensin II, type I receptor-associated protein (AGTRAP) sequences. AGTRAP is known to interact specifically with the C-terminal cytoplasmic region of the angiotensin II type 1 (AT(1)) receptor to regulate different aspects of AT(1) receptor physiology. The function of this family is unclear.
AGTRAP (type-1 angiotensin II receptor-associated protein) appears to be a negative regulator of type-1 angiotensin II receptor-mediated signalling by regulating receptor internalisation as well as mechanism of receptor desensitization such as phosphorylation [ (PUBMED:10358057) ]. It plays an important role in cardiac hypertrophy [ (PUBMED:15757644) ].
Identification and characterization of AGTRAP, a human homolog of murine Angiotensin II Receptor-Associated Protein (Agtrap).
Int J Biochem Cell Biol. 2002; 34: 93-102
Display abstract
Several classes of cytoplasmic proteins have been found to interact specifically with the carboxyl-terminal cytoplasmic region of the angiotensin II type 1 (AT(1)) receptor to regulate different aspects of AT(1) receptor physiology. The murine Angiotensin II Receptor-Associated Protein (Agtrap) is a new member of them. We have recently cloned a new human gene cDNA that codes for a homolog of the murine Agtrap protein from a human fetal brain cDNA library. The deduced polypeptide product of the cDNA is 22 kDa in size, and its DNA and amino acid sequences are 85 and 77% identical to those of the mouse Agtrap gene, respectively. Hence we have named it the human Angiotensin II Receptor-Associated Protein (AGTRAP) gene. The mRNA of AGTRAP was most abundantly expressed in kidney, heart, pancreas and thyroid. Using the yeast two-hybrid screening of a human fetal brain cDNA library, we have identified a new interaction partner of the human AGTRAP protein, RACK1 (Receptor of Activated Protein C Kinase). The AGTRAP-RACK1 interaction was confirmed by GST fusion protein pull-down assays, co-immunoprecipitation and surface plasmon resonance. We suggest that the AGTRAP-RACK1 interaction may help to recruit signaling complex to the AT(1) receptor to affect AT(1) receptor signaling.
Cloning and characterization of ATRAP, a novel protein that interacts with the angiotensin II type 1 receptor.
J Biol Chem. 1999; 274: 17058-62
Display abstract
The carboxyl-terminal cytoplasmic domain of the angiotensin II type 1 (AT1) receptor has recently been shown to interact with several classes of cytoplasmic proteins that regulate different aspects of AT1 receptor physiology. Employing yeast two-hybrid screening of a mouse kidney cDNA library with the carboxyl-terminal cytoplasmic domain of the murine AT1a receptor as a bait, we have isolated a novel protein with a predicted molecular mass of 18 kDa, which we have named ATRAP (for AT1 receptor-associated protein). ATRAP interacts specifically with the carboxyl-terminal domain of the AT1a receptor but not with those of angiotensin II type 2 (AT2), m3 muscarinic acetylcholine, bradykinin B2, endothelin B, and beta2-adrenergic receptors. The mRNA of ATRAP was abundantly expressed in kidney, heart, and testis but was poorly expressed in lung, liver, spleen, and brain. The ATRAP-AT1a receptor association was confirmed by affinity chromatography, by specific co-immunoprecipitation of the two proteins, and by fluorescence microscopy, showing co-localization of these proteins in intact cells. Overexpression of ATRAP in COS-7 cells caused a marked inhibition of AT1a receptor-mediated activation of phospholipase C without affecting m3 receptor-mediated activation. In conclusion, we have isolated a novel protein that interacts specifically with the carboxyl-terminal cytoplasmic domain of the AT1a receptor and affects AT1a receptor signaling.
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