Can I read Internal binding sites for MSH: Analyses in wild-type and variant Cloudman melanoma cells on EtoBox?

Internal binding sites for MSH: Analyses in wild-type and variant Cloudman melanoma cells by Seth J. Orlow; Sara Hotchkiss; John M. Pawelek is a Biochemistry, Genetics and Molecular Biology article available to read on EtoBox.

What is Internal binding sites for MSH: Analyses in wild-type and variant Cloudman melanoma cells about?

Cloudman S91 mouse melanoma cells express both external (plasma membrane) and internal binding sites for MSH. Using '"I-beta melanotropin (P-MSH) as a probe, we report here an extensive series of studies on the biological relevance of these internal sites. Cells were swollen in a hypotonic buffer and lysed, and a particulate fraction was prepared by high-speed centrifugation. This fraction was incubated with '"I-P-MSH with or without excess nonradioactive P-MSH in the cold for 2 hours. The material was then layered onto a step-wise sucrose gradient (8-80%) and centrifuged (1 56,OOOg, 60 min); fractions were collected and counted in a gamma counter or assayed for various enzymatic activities. The following points were established: 1 ) Specific binding sites for MSH were observed sedimenting at an average density of 50% sucrose in amelanotic cells and at higher densities in melanotic cells. 2) These sites were similar in density to those observed when intdct cells were labeled externally with 'L51-P-MSH and then warmed to promote internalization of the hormonc. 3 ) Most of the internal binding sites were not as dense as fully melanired melanosomes. 4) In control experiments, the MSH

Who reads Internal binding sites for MSH: Analyses in wild-type and variant Cloudman melanoma cells?

Author

Seth J. Orlow; Sara Hotchkiss; John M. Pawelek

Publisher

John Wiley and Sons; Wiley (John Wiley & Sons); John Wiley & Sons Inc.; Wiley (ISSN 0021-9541)

Published

1990

Language

EN

Field

Biochemistry, Genetics and Molecular Biology (Life Sciences)