Agonist-promoted Internalization of a Ternary Complex between Calcitonin Receptor-like Receptor, Receptor Activity-modifying Protein 1 (RAMP1), and β-Arrestin

The calcitonin receptor-like receptor (CRLR) is a seven-transmembrane domain (7TM) protein that requires the receptor activity-modifying protein 1 (RAMP1) to be expressed at the cell surface as a functional calcitonin gene-related peptide (CGRP) receptor. Although dimerization between the two molecules is well established, very little is known concerning the trafficking of this heterodimer upon receptor activation. Also, the subcellular localization and biochemical state of this ubiquitously expressed protein, in the absence of CRLR, remains poorly characterized. Here we report that when expressed alone RAMP1 is retained inside the cells where it is found in the endoplasmic reticulum and the Golgi predominantly as a disulfide-linked homodimer. In contrast, when expressed with CRLR, it is targeted to the cell surface as a 1:1 heterodimer with the 7TM protein. Although heterodimer formation does not involve intermolecular disulfide bonds, RAMP-CRLR association promotes the formation of intramolecular disulfide bonds within RAMP1. CGRP binding and receptor activation lead to the phosphorylation of CRLR and the internalization of the receptor as a stable complex. The internalization was found to be both dynamin- and β-arrestin-dependent, indicating that the formation of a ternary complex between CRLR, RAMP1, and β-arrestin leads to clathrin-coated pit-mediated endocytosis. These results therefore indicate that although atypical by its heterodimeric composition and its targeting to the plasma membrane, the CGRP receptor shares endocytotic mechanisms that are common to most classical 7TM receptors. The calcitonin receptor-like receptor (CRLR) is a seven-transmembrane domain (7TM) protein that requires the receptor activity-modifying protein 1 (RAMP1) to be expressed at the cell surface as a functional calcitonin gene-related peptide (CGRP) receptor. Although dimerization between the two molecules is well established, very little is known concerning the trafficking of this heterodimer upon receptor activation. Also, the subcellular localization and biochemical state of this ubiquitously expressed protein, in the absence of CRLR, remains poorly characterized. Here we report that when expressed alone RAMP1 is retained inside the cells where it is found in the endoplasmic reticulum and the Golgi predominantly as a disulfide-linked homodimer. In contrast, when expressed with CRLR, it is targeted to the cell surface as a 1:1 heterodimer with the 7TM protein. Although heterodimer formation does not involve intermolecular disulfide bonds, RAMP-CRLR association promotes the formation of intramolecular disulfide bonds within RAMP1. CGRP binding and receptor activation lead to the phosphorylation of CRLR and the internalization of the receptor as a stable complex. The internalization was found to be both dynamin- and β-arrestin-dependent, indicating that the formation of a ternary complex between CRLR, RAMP1, and β-arrestin leads to clathrin-coated pit-mediated endocytosis. These results therefore indicate that although atypical by its heterodimeric composition and its targeting to the plasma membrane, the CGRP receptor shares endocytotic mechanisms that are common to most classical 7TM receptors. calcitonin gene-related peptide bis(sulfosuccinimidyl)suberate bovine serum albumin calcitonin receptor-like receptor Dulbecco's modified Eagle's medium disuccinimidyl glutarate dithiothreitol fluorescence-activated cell sorting hemagglutinin human embryonic kidney phosphate-buffered saline receptor activity-modifying protein seven transmembrane domain receptor endoplasmic reticulum G protein-coupled receptor The calcitonin gene-related peptide (CGRP)1 is a member of the calcitonin family of regulatory peptides (1Poyner D.R. Biochem. Soc. Trans. 1997; 25: 1032-1036Crossref PubMed Scopus (50) Google Scholar, 2van Rossum D. Hanisch U.K. Quirion R. Neurosci. Biobehav. Rev. 1997; 21: 649-678Crossref PubMed Scopus (455) Google Scholar, 3Wimalawansa S.J. Crit. Rev. Neurobiol. 1997; 11: 167-239Crossref PubMed Scopus (395) Google Scholar). Although a cDNA encoding the calcitonin receptor was cloned over 10 years ago (4Lin H.Y. Harris T.L. Flannery M.S. Aruffo A. Kaji E.H. Gorn A. Kolakowski L.F. Lodish H.F. Goldring S.R. Science. 1991; 254: 1022-1024Crossref PubMed Scopus (427) Google Scholar), it was only recently that McLatchie et al. (5McLatchie L.M. Fraser N.J. Main M.J. Wise A. Brown J. Thompson N. Solari R. Lee M.G. Foord S.M. Nature. 1998; 393: 333-339Crossref PubMed Scopus (1887) Google Scholar) established that co-expression of an orphan calcitonin-receptor like receptor (CRLR) with a newly discovered protein named receptor activity-modifying protein 1 (RAMP1) created a CGRP receptor. CRLR shares 55% amino acid sequence identity with the calcitonin receptor. Both belong to the family B of seven-transmembrane domain (7TM) receptor. The family also includes the receptors for parathyroid hormone, parathyroid hormone-related protein, secretin, glucagon, and vasoactive intestinal polypeptide/pituitary adenylate cyclase activating polypeptide (6Njuki F. Nicholl C.G. Howard A. Mak J.C. Barnes P.J. Girgis S.I. Legon S. Clin. Sci. (Colch.). 1993; 85: 385-388Crossref Scopus (131) Google Scholar, 7Fluhmann B. Muff R. Hunziker W. Fischer J.A. Born W. Biochem. Biophys. Res. Commun. 1995; 206: 341-347Crossref PubMed Scopus (128) Google Scholar). RAMP1, for its part, is a member of a family that comprises 3 members designed RAMP1, RAMP2, and RAMP3. These small intrinsic membrane proteins share less than 30% of sequence identity and possess a large extracellular N terminus (∼100 amino acids), a single transmembrane domain, and a very short intracellular domain (10 amino acids) (5McLatchie L.M. Fraser N.J. Main M.J. Wise A. Brown J. Thompson N. Solari R. Lee M.G. Foord S.M. Nature. 1998; 393: 333-339Crossref PubMed Scopus (1887) Google Scholar). One of the roles proposed for these proteins is that of chaperone/escort promoting the cell surface targeting of CRLR (5McLatchie L.M. Fraser N.J. Main M.J. Wise A. Brown J. Thompson N. Solari R. Lee M.G. Foord S.M. Nature. 1998; 393: 333-339Crossref PubMed Scopus (1887) Google Scholar, 8Foord S.M. Marshall F.H. Trends Pharmacol. Sci. 1999; 20: 184-187Abstract Full Text Full Text PDF PubMed Scopus (149) Google Scholar). Interestingly, like CRLR, RAMPs are also retained intracellularly when expressed alone suggesting that an interaction between the two proteins is essential to their common cell surface expression (5McLatchie L.M. Fraser N.J. Main M.J. Wise A. Brown J. Thompson N. Solari R. Lee M.G. Foord S.M. Nature. 1998; 393: 333-339Crossref PubMed Scopus (1887) Google Scholar, 9Fraser N.J. Wise A. Brown J. McLatchie L.M. Main M.J. Foord S.M. Mol. Pharmacol. 1999; 55: 1054-1059Crossref PubMed Scopus (173) Google Scholar, 10Kuwasako K. Shimekake Y. Masuda M. Nakahara K. Yoshida T. Kitaura M. Kitamura K. Eto T. Sakata T. J. Biol. Chem. 2000; 275: 29602-29609Abstract Full Text Full Text PDF PubMed Scopus (148) Google Scholar, 11Christopoulos G. Perry K.J. Morfis M. Tilakaratne N. Gao Y. Fraser N.J. Main M.J. Foord S.M. Sexton P.M. Mol. Pharmacol. 1999; 56: 235-242Crossref PubMed Scopus (425) Google Scholar). However, the retention site and the fate of each protein, when expressed alone, has never been directly investigated. Given that at least one of the RAMPs is expressed in all tissues tested to date and that they are expressed independently of CRLR (1Poyner D.R. Biochem. Soc. Trans. 1997; 25: 1032-1036Crossref PubMed Scopus (50) Google Scholar, 2van Rossum D. Hanisch U.K. Quirion R. Neurosci. Biobehav. Rev. 1997; 21: 649-678Crossref PubMed Scopus (455) Google Scholar, 3Wimalawansa S.J. Crit. Rev. Neurobiol. 1997; 11: 167-239Crossref PubMed Scopus (395) Google Scholar, 5McLatchie L.M. Fraser N.J. Main M.J. Wise A. Brown J. Thompson N. Solari R. Lee M.G. Foord S.M. Nature. 1998; 393: 333-339Crossref PubMed Scopus (1887) Google Scholar, 12Sexton P.M. Albiston A. Morfis M. Tilakaratne N. Cell. Signal. 2001; 13: 73-83Crossref PubMed Scopus (168) Google Scholar), a better characterization of the subcellular localization of RAMP could shed some light on additional roles that could be played by these proteins. When associated with CRLR, RAMPs has been shown to determine the pharmacological property of the receptor formed. Co-expression of CRLR with RAMP1 leads to a CGRP receptor whereas RAMP 2 or 3 promote the formation of an adrenomedullin receptor (5McLatchie L.M. Fraser N.J. Main M.J. Wise A. Brown J. Thompson N. Solari R. Lee M.G. Foord S.M. Nature. 1998; 393: 333-339Crossref PubMed Scopus (1887) Google Scholar, 9Fraser N.J. Wise A. Brown J. McLatchie L.M. Main M.J. Foord S.M. Mol. Pharmacol. 1999; 55: 1054-1059Crossref PubMed Scopus (173) Google Scholar). Although the contribution of RAMPs to the formation and trafficking of functional receptors has now been well established (13Aldecoa A. Gujer R. Fischer J.A. Born W. FEBS Lett. 2000; 471: 156-160Crossref PubMed Scopus (54) Google Scholar, 14Leuthäuser K. Gujer R. Aldecoa A. McKinney Muff R. Fischer J.A. Born W. Biochem. J. 2000; PubMed Scopus Google Scholar, S. Foord S.M. Marshall F.H. M. J. Biol. Chem. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar), the fate of the complex by has not been investigated. G protein-coupled receptors been shown to internalization classical endocytosis. In these phosphorylation of the receptor by a G protein-coupled receptor has been shown to promote association with β-arrestin to its interaction with and the protein J. Biol. Chem. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar, J. J.A. M.G. Sci. S. A. 1999; PubMed Scopus Google Scholar, Rev. Pharmacol. 1998; PubMed Scopus Google Scholar, Pharmacol. Rev. 2001; Google Scholar). as the as a stable complex with β-arrestin like the the receptor upon internalization J. M.G. J. Biol. Chem. 1999; Full Text Full Text PDF PubMed Scopus Google Scholar). and less well endocytotic has also been proposed for some receptors Rev. Pharmacol. 1998; PubMed Scopus Google M. J. W. J. Sci. 1998; PubMed Google Scholar, Y. S. T. J. Biol. Chem. 2000; 275: Full Text Full Text PDF PubMed Scopus Google Scholar, S. F. J. J. R. Mol. Pharmacol. 2001; PubMed Scopus Google Scholar, R. J. B. Res. 2001; Scopus Google Scholar). internalization of CRLR has been K. Shimekake Y. Masuda M. Nakahara K. Yoshida T. Kitaura M. Kitamura K. Eto T. Sakata T. J. Biol. Chem. 2000; 275: 29602-29609Abstract Full Text Full Text PDF PubMed Scopus (148) Google Scholar) the mechanisms in the of this atypical receptor not been investigated. very little is known concerning the fate of RAMPs RAMP 2 and 3 found in the a of with adrenomedullin K. Shimekake Y. Masuda M. Nakahara K. Yoshida T. Kitaura M. Kitamura K. Eto T. Sakata T. J. Biol. Chem. 2000; 275: 29602-29609Abstract Full Text Full Text PDF PubMed Scopus (148) Google Scholar), the are as a stable complex remains to be In this a of RAMP1 and CRLR subcellular to determine CRLR, is retained in the endoplasmic reticulum when expressed alone, RAMP1 is found both in the and the Golgi in the absence of CRLR indicating a additional for RAMP1 that could involve between the two of cells CRLR and RAMP1, the complex phosphorylation of the CRLR not the RAMP that is by dynamin- and The complex is as a stable ternary complex β-arrestin that remains associated with it is was and and disuccinimidyl glutarate and and and by as and was was The was was was and and The expression for RAMP1, CRLR, and as (5McLatchie L.M. Fraser N.J. Main M.J. Wise A. Brown J. Thompson N. Solari R. Lee M.G. Foord S.M. Nature. 1998; 393: 333-339Crossref PubMed Scopus (1887) Google Scholar, S. A. S. D. M. M. Sci. S. A. 2000; Google Scholar). The was by S. S. G. of and the in a J. embryonic kidney cells in modified medium with 2 at in a of and cells receptor or by on cells with encoding each protein and the cell cloned by and expression by binding or Y. T. Cell. Full Text PDF PubMed Scopus Google Scholar). in or in to and with the cells or with in phosphate-buffered saline for and for 10 with in The cells with in for 1 The at or and The in and in the with the for of or and for of or at for in the the was on a a or cells determine expression of both cells in in for on and for 1 with in in and with in for as in the for of or for the of cells or with RAMP1 and or CRLR and whereas alone was in cells or receptors. with cells in for or in the for 1 The cells and with the or 1 for at The internalization was on and the cells in in for The cells as the for of the receptors and RAMP1. The and the by as as cells with CRLR and or and RAMP1 with and with in for 1 at The cells in 2 and in cell sorting was on a was by and cells in each in with and for at in a 1 and at for at was by or to the an at protein was for an additional 3 by and with and The was in with or and for in in and with for 1 on cells with or in on for 1 in and in the the cells and for as by 10 or to and to or was for or both in in and on for 1 in 1 The was by in and for as an of 1 in medium cells or and for 2 in medium and with CGRP for the in 10 10 and at for at was as by to and was with with in with or an a 1 in cells for with internalization and to for the at The cells with and in 1 for 1 membrane as (5McLatchie L.M. Fraser N.J. Main M.J. Wise A. Brown J. Thompson N. Solari R. Lee M.G. Foord S.M. Nature. 1998; 393: 333-339Crossref PubMed Scopus (1887) Google Scholar) and in 1 for 1 The was in and the cells for and for as was by and the results the that both CRLR and RAMP1 are retained inside the cell when expressed (5McLatchie L.M. Fraser N.J. Main M.J. Wise A. Brown J. Thompson N. Solari R. Lee M.G. Foord S.M. Nature. 1998; 393: 333-339Crossref PubMed Scopus (1887) Google Scholar, 9Fraser N.J. Wise A. Brown J. McLatchie L.M. Main M.J. Foord S.M. Mol. Pharmacol. 1999; 55: 1054-1059Crossref PubMed Scopus (173) Google Scholar, 10Kuwasako K. Shimekake Y. Masuda M. Nakahara K. Yoshida T. Kitaura M. Kitamura K. Eto T. Sakata T. J. Biol. Chem. 2000; 275: 29602-29609Abstract Full Text Full Text PDF PubMed Scopus (148) Google Scholar, 11Christopoulos G. Perry K.J. Morfis M. Tilakaratne N. Gao Y. Fraser N.J. Main M.J. Foord S.M. Sexton P.M. Mol. Pharmacol. 1999; 56: 235-242Crossref PubMed Scopus (425) Google Scholar). However, the site of retention for the two proteins has not been the subcellular of CRLR and RAMP1 was by shown in at the surface of cells or with the cell surface localization of the two proteins when the cells with and and when was in the cells and G and the of the two proteins at the plasma membrane upon determine the intracellular site of retention of each protein expressed with the endoplasmic reticulum and Golgi D. D. D. J. Biol. Chem. 1991; Full Text PDF PubMed Google Scholar) and J. Biol. Chem. Full Text PDF PubMed Google Scholar), was was found to with not 2 indicating that it is retained in the in the absence of In contrast, was found to with both and suggesting that RAMP1 the to the Golgi in the absence of CRLR 2 Given that could be at the cell surface in the absence of CRLR, these that RAMP1 alone be the to the trafficking between the and the Golgi has been for as and membrane protein that are known to as receptors for the of the to the or Golgi F. Biol. 1999; PubMed Scopus Google Scholar, J. K. J. Sci. 1999; PubMed Google Scholar, F. J. Sci. 2000; PubMed Google Scholar), suggesting that RAMPs additional roles that are of their association with The Golgi expression of RAMP is not a it was in stable with a of expression not expression of a CRLR never to Golgi expression not localization of and expressed The subcellular of and was by in cells and and the to and the with the and Golgi was by of the these results that when expressed the CRLR is retained in the RAMP1 be the to the the two proteins to in the their association the complex to the Golgi to the plasma the of CRLR on the cell surface expression of RAMP1 and to that expressed at the cell CRLR and RAMP1 as a stable and cell surface of and In the absence of 3 3 and was in the was at the cell surface with the in However, when and and RAMP1 was both in the and at the cell RAMP1 was found to be associated with CRLR could be with both in and upon cell surface indicating that the complex stable the two proteins the plasma was also upon and cell surface of not determine the interaction between CRLR and RAMP1 is or an additional the membrane shown in 3 on the of or when expressed However, when the two proteins and a of was in to the of and The in for upon in the absence of is with the (5McLatchie L.M. Fraser N.J. Main M.J. Wise A. Brown J. Thompson N. Solari R. Lee M.G. Foord S.M. Nature. 1998; 393: 333-339Crossref PubMed Scopus (1887) Google Scholar, 9Fraser N.J. Wise A. Brown J. McLatchie L.M. Main M.J. Foord S.M. Mol. Pharmacol. 1999; 55: 1054-1059Crossref PubMed Scopus (173) Google Scholar) Golgi that results the interaction between the two proteins. of was in and with a of a of the receptor the complex of The of the in the not be as for the of CRLR at the cell surface most the of The of the complex is with a interaction between one of RAMP1 and one of receptor of RAMP1 could be in the absence of CRLR, in the absence of suggesting the of of RAMP1 that are at least to for RAMP1 and (5McLatchie L.M. Fraser N.J. Main M.J. Wise A. Brown J. Thompson N. Solari R. Lee M.G. Foord S.M. Nature. 1998; 393: 333-339Crossref PubMed Scopus (1887) Google Scholar, 12Sexton P.M. Albiston A. Morfis M. Tilakaratne N. Cell. Signal. 2001; 13: 73-83Crossref PubMed Scopus (168) Google Scholar), their with the formation of has not been investigated. that in the of CRLR, expressed as and to and is retained In the was the whereas the was in the of of disulfide contribution in these lead to a or to intramolecular for dimerization be at this However, the does not cell it was not by as Co-expression of CRLR the expression of RAMP1 and the that the the that the formation of heterodimer is over that of RAMP1 as a of a of RAMP1 or the of the RAMP1 a stable complex. Given the of that be to the disulfide bonds in the RAMP1 the Interestingly, the formation of the complex is associated with a in the of the RAMP1 when with CRLR when expressed that most the formation of intramolecular disulfide the was found to be to whereas the that is upon CRLR co-expression is to its and to a that has the as RAMP1 expressed alone these results indicate that CRLR interaction promotes that involve disulfide that are in the RAMP1 homodimer. The interaction between CRLR and the RAMP was by the of with Although to in disulfide the interaction between RAMP1 and CRLR most not involve intermolecular bonds K. Gujer R. Aldecoa A. McKinney Muff R. Fischer J.A. Born W. Biochem. J. 2000; PubMed Scopus Google Scholar). In to the RAMP1 the is at the cell the RAMP1 could be only in indicating that it is retained with the that when expressed alone, RAMP1 not CRLR is in the these indicate that the RAMP1 has a Although is to this RAMP1, and share with proteins as that been shown to disulfide-linked and in the F. J. Sci. 2000; PubMed Google Scholar). indicate a for RAMP1 in the protein determine binding of the receptor to its the the of short CGRP for was shown in CGRP on the of that could be with suggesting a stable interaction between RAMP1 and CRLR CGRP However, CGRP to the phosphorylation of the receptor of both and cells with an of CRLR not RAMP1 phosphorylation is a well known 7TM receptors and is associated with the that receptor activation. The that CRLR phosphorylation was within the of the is with a of phosphorylation for this receptor. of the cyclase activation has been in cells A. S.R. A. 1999; PubMed Google Scholar). has also been shown to the internalization that upon receptor activation Pharmacol. Rev. 2001; Google Scholar). Given that CRLR not RAMP1 to be the internalization of both proteins was investigated. The internalization of CRLR and RAMP1 by in cells and RAMP1 or CRLR and a and in cell surface that to a of of the of an internalization upon CGRP suggesting that both proteins directly determine the two proteins as a the fate of the heterodimer was The of the cell the of at the cell surface the of CGRP whereas the cell has to the of the and was with the shown in to the the and the complex Although not a of to was also a of cell surface by was that of the complex the cell surface in less than 10 and In contrast, CGRP very little in the of by and that the in heterodimer results its internalization and not its is with the that the interaction between the two proteins remains stable upon is also in with the intracellular of CRLR and or by et al. K. Shimekake Y. Masuda M. Nakahara K. Yoshida T. Kitaura M. Kitamura K. Eto T. Sakata T. J. Biol. Chem. 2000; 275: 29602-29609Abstract Full Text Full Text PDF PubMed Scopus (148) Google Scholar) adrenomedullin The internalization was by B and with classical clathrin-coated and in with the that CRLR with upon of cells with CGRP K. Shimekake Y. Masuda M. Nakahara K. Yoshida T. Kitaura M. Kitamura K. Eto T. Sakata T. J. Biol. Chem. 2000; 275: 29602-29609Abstract Full Text Full Text PDF PubMed Scopus (148) Google Scholar). The of CGRP most results the of the receptor a in CRLR was in the absence of and that is is that the of the and not the intracellularly retained is is most to the phosphorylation of the receptor that we in B. determine the mechanisms in the internalization of the the roles of β-arrestin and by their F. J. Biol. Chem. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar) and J. M.G. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). The of the of and the on the internalization of the complex both and In cells both and RAMP1 or CRLR and that the in cell surface expression of both and to and The internalization of the complex was also found to be by the two the these results indicate the of the classical clathrin-coated of the only on the of the complex internalization by and indicating that the of β-arrestin expression in cells is to promote endocytosis. is with the of the receptor in the cell F. J. Biol. Chem. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar, M.G. Science. PubMed Scopus Google Scholar). The of by the could be as an of a of this regulatory protein in internalization as has been proposed for F. J. Biol. Chem. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar, M. G. Mol. 1998; PubMed Google Scholar, F. D. A. Y. Mol. 1999; 13: PubMed Scopus Google Scholar, J. Biol. Chem. 1999; Full Text Full Text PDF PubMed Scopus Google Scholar). However, receptor internalization by with and not by association F. J. Biol. Chem. 1997; Full Text Full Text PDF PubMed Scopus Google Scholar), it is that the could a with the and is not of β-arrestin The of β-arrestin and its by the receptor was by this a was with and RAMP1 or CRLR and surface CRLR or RAMP1 with and to The subcellular of the proteins was by and of the shown in and was at the cell surface was found in the as a was when cells the or the receptors with a CGRP the was where it with and is very to the one receptor is is for the receptor of and cells the CRLR with RAMP1, with CRLR, the receptor or the receptor with These cells with or to a or at with or 1 The cells and with or to RAMP1 or the receptors was in The in the β-arrestin has been to of the regulatory protein for receptors. The of the receptor and β-arrestin in endocytotic as it is the for the receptor was as of a stable interaction between the receptor and The of internalization of β-arrestin upon a of β-arrestin the receptor internalization J.A. M.G. J. Biol. Chem. 1999; Full Text Full Text PDF PubMed Scopus Google Scholar, J.A. M.G. J. Biol. Chem. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). The results with the complex the of β-arrestin in CGRP receptor internalization and that it to the of receptor that a interaction with this regulatory protein J.A. M.G. J. Biol. Chem. 1999; Full Text Full Text PDF PubMed Scopus Google Scholar, J.A. M.G. J. Biol. Chem. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). The of the in the that the CGRP receptor is a stable complex of CRLR and RAMP1. that a ternary and as a for the endocytotic that of in the of the receptor are for the interaction with β-arrestin J.A. M.G. J. Biol. Chem. 1999; Full Text Full Text PDF PubMed Scopus Google Scholar, J.A. M.G. J. Biol. Chem. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). sequence is in the short of RAMP1 whereas a sequence is found in the of the CRLR, suggesting that it is an interaction with the receptor that β-arrestin promotes the internalization of the complex. When receptors to the family B of both and internalization been the hormone, the vasoactive intestinal polypeptide 1 and the of β-arrestin in the internalization was found M. G. Mol. 1998; PubMed Google Scholar, J. Biol. Chem. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar, A. Perry S.J. M. Sci. S. A. 2000; PubMed Scopus (148) Google Scholar, S. M.G. J. Biol. Chem. 1999; Full Text Full Text PDF PubMed Scopus Google Scholar) whereas a of β-arrestin the internalization of the and the parathyroid receptors T. N. S. G. Mol. Pharmacol. 2001; PubMed Scopus Google Scholar, A. M. R. 2000; PubMed Scopus Google Scholar, M. M. A. J. Biol. Chem. 1999; Full Text Full Text PDF PubMed Scopus Google Scholar). In the results the that CRLR and RAMP1 a stable complex that as a CGRP receptor. The complex to be in the is to the cell surface and activation by Although atypical by its heterodimeric composition that is for targeting to the plasma membrane, the CGRP receptor shares endocytotic mechanisms that are common to most classical 7TM receptor. of β-arrestin in the internalization that phosphorylation by G protein-coupled receptor as has been shown for receptors Pharmacol. Rev. 2001; Google Scholar), is in with this phosphorylation of the CGRP receptor by G protein-coupled receptor was recently N. J. K. J. Pharmacol. 2000; PubMed Scopus Google Scholar). The that the of RAMP1 CRLR a interaction with now as the 7TM and CRLR and RAMP1, to as a complex. an between RAMPs and CRLR does it most at the or Golgi In that it is that RAMP1 expressed alone was found both in the and Golgi CRLR in the absence of RAMP1 was to the The in the of the disulfide found within RAMP1 on a complex with CRLR a complex of upon association with the roles of RAMPs as and on the of in in a of at least two CRLR and calcitonin receptor. receptor mechanisms that a small The are to for of the

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.