Search Results

You are looking at 1 - 1 of 1 items for

  • Author: A Millest x
  • Refine by access: All content x
Clear All Modify Search
M Egerton
Search for other papers by M Egerton in
Google Scholar
PubMed
Close
,
M Needham
Search for other papers by M Needham in
Google Scholar
PubMed
Close
,
S Evans
Search for other papers by S Evans in
Google Scholar
PubMed
Close
,
A Millest
Search for other papers by A Millest in
Google Scholar
PubMed
Close
,
G Cerillo
Search for other papers by G Cerillo in
Google Scholar
PubMed
Close
,
J McPheat
Search for other papers by J McPheat in
Google Scholar
PubMed
Close
,
M Popplewell
Search for other papers by M Popplewell in
Google Scholar
PubMed
Close
,
D Johnstone
Search for other papers by D Johnstone in
Google Scholar
PubMed
Close
, and
M Hollis
Search for other papers by M Hollis in
Google Scholar
PubMed
Close

ABSTRACT

The human breast carcinoma cell line T47D is known to express high-affinity calcitonin receptors (CTRs). PCR amplification of the CTR cDNA from T47D mRNA resulted in the identification of two different cDNAs that encode distinct receptor isoforms, hαCTR and hβCTR. The two cDNAs are identical except that the hαCTR cDNA contains a 48 bp insert sequence that encodes a 16 amino acid domain in the first cytosolic loop of the receptor. Stable transfection of each receptor cDNA into murine erythroleukaemia (MEL) cells resulted in the expression of receptors with high affinity for radiolabelled salmon calcitonin (hαCTR Kd 0·09 nm, hβCTR Kd 0·12 nm). Ligand competition binding studies did not reveal any significant pharmacological difference between the receptor isoforms. In transfected MEL cells and COS-1 cells the hβCTR isoform was expressed at tenfold higher levels than the hαCTR. A reporter gene assay that monitored the coupling of CTR to adenylate cyclase by increases in β-galactosidase activity indicated that both receptors were able to stimulate cyclic AMP production in response to ligand binding.

Restricted access