Heterogeneity of the MSH Receptor Among B16 Murine Melanoma Subclones

Abstract

The heterogeneity of melanotropin receptors on B16 sublines was tested by using photoaffinity crosslinking techniques and the superpotent α-MSH derivative Nle⁴ D-Phe⁷, 1′-(2–nitro-4–azido-phenylsulfenyl)-Trp⁹]-α-MSH (NAPS-MSH). Specific crosslinking of this compound to B16–F1, B16–F10, B16–M2R or B16–W4 cells revealed three different subtypes of MSH receptor based on SDS-PAGE analysis. Binding of monoiodinated α-MSH to these different subclones is saturable and characteristic for a single class of complexes (0.9 nM < K_D < 1.6 nM). In this article the nature of the different MSH receptor subtypes as well as their possible correlation to the melanogenic potential of a particular cell line is discussed.