Abstract
Specific binding sites for 125I-labelled human luteinizing hormone (hLH) were detected in microsomal and cytosolic fractions from Saccharomyces cerevisiae, Neurospora crassa and a wall-less (‘slime’) mutant of N. crassa. Scatchard analysis of hLH-binding to microscomes revealed the presence of both high affinity (Ka of 60–70 × 1010m−1) and lower affinity (Ka of 1·3–1·9 × 1010m−1) binding sites in each organism. 125I-hLH binding to both S. cerevisiae and N. crassa (wild type) microsomes was inhibited by low concentrations of Ca2+ and Mg2+ (30 μm), and by higher concentrations of Na+ and K+ (40 mm). Binding was also inhibited, in dose-dependent fashion, by partially-purified preparations of hLH and hCG. In contrast, highly purified hCG preparations were much less potent, though they strongly inhibited hLH binding to sheep corpus luteum LH-receptors. Moreover, high-purified hCG β-core protein inhibited hLH binding to S. cerevisiae and N. crassa microsomes in a dose-dependent manner, but had no effect on hLH binding to sheep luteal receptors. The properties of the S. cerevisiae and N. crassa LH-binding sites are similar to those of binders detected previously in Candida albicans. Thus, interactions between hLH-like molecules and their receptors may have a widespread distribution in the Ascomycotina and Deuteromycotina.
Original language | English |
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Pages (from-to) | 1229-1234 |
Number of pages | 6 |
Journal | Mycological Research |
Volume | 98 |
Issue number | 11 |
DOIs | |
Publication status | Published - 1994 |
Funding
This work was supported in part by grants from the MRC, SERC, Wellcome Trust and Glaxo Group Research Ltd. We thank Dr R. A. Radford for providing the N. crassa strains, the Hormone Distribution Officer, NIADD, U.S.A. for the generous gifts of purified ovine gonadotropin and human growth honnone, Drs B. Nisula and D. Blithe, NICHHD, NIH, MD, U.S.A. for purified hCG p-core protein, and Dr S. S. Lynch, Women's Hospital, Birmingham, U.K. for highly purified human pituitary gonadotropins.
Funders | Funder number |
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Glaxo Group Research Ltd. | |
The Wellcome Trust |
ASJC Scopus subject areas
- Biotechnology
- Ecology, Evolution, Behavior and Systematics
- Genetics
- Plant Science