Photoaffinity labelling of melanoma cell MSH receptors

SCIMONELLI TN; EBERLE A

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 1987 vol. 226 p. 134 - 134

V-irradiation at 365 nm of cultured Cloudman S91 mouse melanoma cells in the presence of photoreactive a-MSH analogues induced longlasting receptor stimulation as revealed by the ensuing activation of tyrosinase. Receptor labelling was more efficient with 4-diazirinophenyl and 2-nitro-4-azidophenyl photolabels than with 4-azidophenyl, and was further increased when superpotent [Nle4,D-Phe?]-cc-MSH was used as ligand. Incubation of B16 melanoma cell membranes with mono-iodinated [Nle4,D-Phe7,Trp-(Naps)9]-a-MSH followed by UV-irradiation at 31&550 nm labelled a single band on SDS-PAGE with a molecular mass = 45 kDa. The displacement curve obtained in a competitive photolabelling experiment paralleled that of the binding assay, demonstrating that the labelling was specific.