Evidence that the angiotensin IV (AT(4)) receptor is the enzyme insulin-regulated aminopeptidase

Central infusion of angiotensin IV or its more stable analogues facilitates memory retention and retrieval in normal animals and reverses amnesia induced by scopolamine or by bilateral perforant pathway lesions. These peptides bind with high affinity and specificity to a novel binding site designate...

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Bibliographic Details
Published in:The Journal of biological chemistry Vol. 276; no. 52; p. 48623
Main Authors: Albiston, A L, McDowall, S G, Matsacos, D, Sim, P, Clune, E, Mustafa, T, Lee, J, Mendelsohn, F A, Simpson, R J, Connolly, L M, Chai, S Y
Format: Journal Article
Language:English
Published: United States 28.12.2001
Subjects:
Aminopeptidases - antagonists & inhibitors
Aminopeptidases - genetics
Aminopeptidases - isolation & purification
Aminopeptidases - metabolism
Angiotensin II - analogs & derivatives
Angiotensin II - chemistry
Angiotensin II - metabolism
Angiotensin Receptor Antagonists
Animals
Autoradiography
Brain - cytology
Brain - enzymology
Brain - metabolism
Cell Line
Cystinyl Aminopeptidase
Hemoglobins - metabolism
Humans
Immunohistochemistry
In Situ Hybridization
Iodine Radioisotopes - chemistry
Iodine Radioisotopes - metabolism
Mice
Mice, Inbred C57BL
Peptide Fragments - metabolism
Radioligand Assay
Receptors, Angiotensin - genetics
Receptors, Angiotensin - isolation & purification
Receptors, Angiotensin - metabolism
Recombinant Fusion Proteins - metabolism
Transfection
ISSN:0021-9258
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Summary:Central infusion of angiotensin IV or its more stable analogues facilitates memory retention and retrieval in normal animals and reverses amnesia induced by scopolamine or by bilateral perforant pathway lesions. These peptides bind with high affinity and specificity to a novel binding site designated the angiotensin AT(4) receptor. Until now, the AT(4) receptor has eluded molecular characterization. Here we identify the AT(4) receptor, by protein purification and peptide sequencing, to be insulin-regulated aminopeptidase (IRAP). HEK 293T cells transfected with IRAP exhibit typical AT(4) receptor binding characteristics; the AT(4) receptor ligands, angiotensin IV and LVV-hemorphin 7, compete for the binding of [(125)I]Nle(1)-angiotensin IV with IC(50) values of 32 and 140 nm, respectively. The distribution of IRAP and its mRNA in the brain, determined by immunohistochemistry and hybridization histochemistry, parallels that of the AT(4) receptor determined by radioligand binding. We also show that AT(4) receptor ligands dose-dependently inhibit the catalytic activity of IRAP. We have therefore demonstrated that the AT(4) receptor is IRAP and propose that AT(4) receptor ligands may exert their effects by inhibiting the catalytic activity of IRAP thereby extending the half-life of its neuropeptide substrates.
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ISSN:0021-9258
DOI:10.1074/jbc.C100512200