Amylin receptor phenotypes derived from human calcitonin receptor/RAMP coexpression exhibit pharmacological differences dependent on receptor isoform and host cell environment.

Nanda Tilakaratne, George Christopoulos, Emma T Zumpe, Steven M Foord, Patrick M Sexton

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126 Citations (Scopus)

Abstract

Receptor activity modifying proteins (RAMPs) constitute a group of three proteins, designated as RAMP1, 2, and 3, which are able to effect functional changes in some members of the G protein-coupled receptor family. Thus, RAMP1 or RAMP3 can modify the calcitonin receptor (CTR) to also function as a high-affinity amylin receptor-like phenotype. To examine the RAMP/CTR interaction, individual RAMPs were coexpressed with either of the two human CTR (hCTR) isoforms, the insert negative (hCTR(I1-)) or the insert positive (hCTR(I1+)), in Chinese hamster ovary (CHO-P) or African monkey kidney (COS-7) cells. CHO-P cells provide an environment conducive to a low, but significant, level of amylin binding with either hCTR isoform alone, unlike in COS-7, where RAMP coexpression is imperative for amylin binding. Also, in CHO-P, hCTR(I1-) induced amylin binding with all three RAMPs, in contrast to COS-7, where only RAMP1 or RAMP3 generate an amylin receptor phenotype. hCTR(I1+) induced high-affinity amylin binding with any RAMP in either cell line. In COS-7 cells, hCTR(I1+)/RAMP-generated receptor displayed high- and low-affinity states, in contrast with the single-state binding seen with hCTR(I1-)/RAMP-generated receptor, whereas in CHO-P cells a two-affinity state receptor phenotype was evident with both hCTR isoforms. Endogenous RAMP expression is low and similar between cell lines. The results suggest that CTR/RAMP interaction in these cells is complex with other cellular factors such as the levels of different G proteins and/or receptor/RAMP stoichiometry following heterologous coexpression contributing to the ultimate receptor phenotype.
Original languageEnglish
Pages (from-to)61-72
Number of pages12
JournalJournal of Pharmacology and Experimental Therapeutics
Volume294
Issue number1
Publication statusPublished - Jul 2000
Externally publishedYes

Cite this

@article{81a72a40866b44a780b96fb0bbf9483e,
title = "Amylin receptor phenotypes derived from human calcitonin receptor/RAMP coexpression exhibit pharmacological differences dependent on receptor isoform and host cell environment.",
abstract = "Receptor activity modifying proteins (RAMPs) constitute a group of three proteins, designated as RAMP1, 2, and 3, which are able to effect functional changes in some members of the G protein-coupled receptor family. Thus, RAMP1 or RAMP3 can modify the calcitonin receptor (CTR) to also function as a high-affinity amylin receptor-like phenotype. To examine the RAMP/CTR interaction, individual RAMPs were coexpressed with either of the two human CTR (hCTR) isoforms, the insert negative (hCTR(I1-)) or the insert positive (hCTR(I1+)), in Chinese hamster ovary (CHO-P) or African monkey kidney (COS-7) cells. CHO-P cells provide an environment conducive to a low, but significant, level of amylin binding with either hCTR isoform alone, unlike in COS-7, where RAMP coexpression is imperative for amylin binding. Also, in CHO-P, hCTR(I1-) induced amylin binding with all three RAMPs, in contrast to COS-7, where only RAMP1 or RAMP3 generate an amylin receptor phenotype. hCTR(I1+) induced high-affinity amylin binding with any RAMP in either cell line. In COS-7 cells, hCTR(I1+)/RAMP-generated receptor displayed high- and low-affinity states, in contrast with the single-state binding seen with hCTR(I1-)/RAMP-generated receptor, whereas in CHO-P cells a two-affinity state receptor phenotype was evident with both hCTR isoforms. Endogenous RAMP expression is low and similar between cell lines. The results suggest that CTR/RAMP interaction in these cells is complex with other cellular factors such as the levels of different G proteins and/or receptor/RAMP stoichiometry following heterologous coexpression contributing to the ultimate receptor phenotype.",
author = "Nanda Tilakaratne and George Christopoulos and Zumpe, {Emma T} and Foord, {Steven M} and Sexton, {Patrick M}",
year = "2000",
month = "7",
language = "English",
volume = "294",
pages = "61--72",
journal = "Journal of Pharmacology and Experimental Therapeutics",
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Amylin receptor phenotypes derived from human calcitonin receptor/RAMP coexpression exhibit pharmacological differences dependent on receptor isoform and host cell environment. / Tilakaratne, Nanda; Christopoulos, George; Zumpe, Emma T; Foord, Steven M; Sexton, Patrick M.

In: Journal of Pharmacology and Experimental Therapeutics, Vol. 294, No. 1, 07.2000, p. 61-72.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Amylin receptor phenotypes derived from human calcitonin receptor/RAMP coexpression exhibit pharmacological differences dependent on receptor isoform and host cell environment.

AU - Tilakaratne, Nanda

AU - Christopoulos, George

AU - Zumpe, Emma T

AU - Foord, Steven M

AU - Sexton, Patrick M

PY - 2000/7

Y1 - 2000/7

N2 - Receptor activity modifying proteins (RAMPs) constitute a group of three proteins, designated as RAMP1, 2, and 3, which are able to effect functional changes in some members of the G protein-coupled receptor family. Thus, RAMP1 or RAMP3 can modify the calcitonin receptor (CTR) to also function as a high-affinity amylin receptor-like phenotype. To examine the RAMP/CTR interaction, individual RAMPs were coexpressed with either of the two human CTR (hCTR) isoforms, the insert negative (hCTR(I1-)) or the insert positive (hCTR(I1+)), in Chinese hamster ovary (CHO-P) or African monkey kidney (COS-7) cells. CHO-P cells provide an environment conducive to a low, but significant, level of amylin binding with either hCTR isoform alone, unlike in COS-7, where RAMP coexpression is imperative for amylin binding. Also, in CHO-P, hCTR(I1-) induced amylin binding with all three RAMPs, in contrast to COS-7, where only RAMP1 or RAMP3 generate an amylin receptor phenotype. hCTR(I1+) induced high-affinity amylin binding with any RAMP in either cell line. In COS-7 cells, hCTR(I1+)/RAMP-generated receptor displayed high- and low-affinity states, in contrast with the single-state binding seen with hCTR(I1-)/RAMP-generated receptor, whereas in CHO-P cells a two-affinity state receptor phenotype was evident with both hCTR isoforms. Endogenous RAMP expression is low and similar between cell lines. The results suggest that CTR/RAMP interaction in these cells is complex with other cellular factors such as the levels of different G proteins and/or receptor/RAMP stoichiometry following heterologous coexpression contributing to the ultimate receptor phenotype.

AB - Receptor activity modifying proteins (RAMPs) constitute a group of three proteins, designated as RAMP1, 2, and 3, which are able to effect functional changes in some members of the G protein-coupled receptor family. Thus, RAMP1 or RAMP3 can modify the calcitonin receptor (CTR) to also function as a high-affinity amylin receptor-like phenotype. To examine the RAMP/CTR interaction, individual RAMPs were coexpressed with either of the two human CTR (hCTR) isoforms, the insert negative (hCTR(I1-)) or the insert positive (hCTR(I1+)), in Chinese hamster ovary (CHO-P) or African monkey kidney (COS-7) cells. CHO-P cells provide an environment conducive to a low, but significant, level of amylin binding with either hCTR isoform alone, unlike in COS-7, where RAMP coexpression is imperative for amylin binding. Also, in CHO-P, hCTR(I1-) induced amylin binding with all three RAMPs, in contrast to COS-7, where only RAMP1 or RAMP3 generate an amylin receptor phenotype. hCTR(I1+) induced high-affinity amylin binding with any RAMP in either cell line. In COS-7 cells, hCTR(I1+)/RAMP-generated receptor displayed high- and low-affinity states, in contrast with the single-state binding seen with hCTR(I1-)/RAMP-generated receptor, whereas in CHO-P cells a two-affinity state receptor phenotype was evident with both hCTR isoforms. Endogenous RAMP expression is low and similar between cell lines. The results suggest that CTR/RAMP interaction in these cells is complex with other cellular factors such as the levels of different G proteins and/or receptor/RAMP stoichiometry following heterologous coexpression contributing to the ultimate receptor phenotype.

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M3 - Article

VL - 294

SP - 61

EP - 72

JO - Journal of Pharmacology and Experimental Therapeutics

JF - Journal of Pharmacology and Experimental Therapeutics

SN - 0022-3565

IS - 1

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