Identification of Mel1a melatonin receptors in the human embryonic kidney cell line HEK293: evidence of G protein-coupled melatonin receptors which do not mediate the inhibition of stimulated cyclic AMP levels

S Conway; J E Drew; S J Canning; P Barrett; R Jockers; A D Strosberg; B Guardiola-Lemaitre; P Delagrange; P J Morgan

doi:10.1016/s0014-5793(97)00315-3

Identification of Mel1a melatonin receptors in the human embryonic kidney cell line HEK293: evidence of G protein-coupled melatonin receptors which do not mediate the inhibition of stimulated cyclic AMP levels

FEBS Lett. 1997 Apr 21;407(1):121-6. doi: 10.1016/s0014-5793(97)00315-3.

Authors

S Conway¹, J E Drew, S J Canning, P Barrett, R Jockers, A D Strosberg, B Guardiola-Lemaitre, P Delagrange, P J Morgan

Affiliation

¹ Molecular Neuroendocrinology Group, Rowett Research Institute, Bucksburn, Aberdeen, UK. sco@rri.sari.ac.uk

PMID: 9141494
DOI: 10.1016/s0014-5793(97)00315-3

Abstract

Binding assays using 2-[125I]iodomelatonin revealed high-affinity, guanosine 5'-O-(3-thiotriphosphate) sensitive, melatonin binding sites (B(max) 1.1 fmol/mg protein) in the human embryonic kidney cell line HEK293. Competition studies using the selective melatonin receptor antagonist luzindole and RT-PCR techniques identified these sites as human Mel1a melatonin receptors. Challenge of HEK293 cells with 1 microM melatonin had no effect on forskolin stimulated cyclic AMP levels, whereas in HEK293 cells engineered to stably over-express the human Mel1a melatonin receptor (B(max) > 400 fmol/mg protein) melatonin dose-dependently inhibited stimulated cyclic AMP levels (IC50 7.7 pM). These data may indicate that certain tissues, expressing low levels of G protein-coupled melatonin receptors, do not display melatonin mediated inhibition of cAMP.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Binding, Competitive
Cell Line
Colforsin / pharmacology
Cyclic AMP / metabolism
GTP-Binding Proteins / metabolism*
Genomic Library
Humans
Kidney / cytology
Kidney / embryology
Kidney / metabolism*
Melatonin / analogs & derivatives
Melatonin / metabolism*
RNA, Messenger / genetics
Receptors, Cell Surface / genetics
Receptors, Cell Surface / metabolism*
Receptors, Cytoplasmic and Nuclear / genetics
Receptors, Cytoplasmic and Nuclear / metabolism*
Receptors, Melatonin
Sequence Analysis, DNA
Serotonin / analogs & derivatives
Serotonin / metabolism
Signal Transduction
Tryptamines / metabolism

Substances

RNA, Messenger
Receptors, Cell Surface
Receptors, Cytoplasmic and Nuclear
Receptors, Melatonin
Tryptamines
luzindole
Colforsin
Serotonin
2-iodomelatonin
Cyclic AMP
GTP-Binding Proteins
Melatonin
N-acetylserotonin
6-hydroxymelatonin