The β-adrenergic receptor in the human neutrophil plasma membrane: receptor-cyclase uncoupling is associated with amplified GTP activation
Abstract
We compared the properties of the adenylate cyclase system in plasma membranes derived from gas cavitation and sonication of human neutrophils. In membranes prepared from cavitated cells, cyclase was stimulated by fluoride ion and Gpp(NH)p. Stimulation by isoproterenol (and PGE1) was absent, although the β-receptor was present as judged by 125I-HYP binding. Two unusual characteristics of this cyclase system are a) substantial activation of cyclase by GTP in the absence of hormone, and b) reduction in the regulation of the β-receptor by GTP. By contrast, vesicles isolated from sonicated cells displayed normal GTP-dependent activation by isoproterenol (as well as PGE1) and GTP regulation of the β-receptor, while hormone-independent stimulation by GTP was negligible. Cholera toxin-catalyzed ADP ribosylation revealed a prominent band at 42K in both membranes, and a minor band at 35K, although the degree of labeling of this protein was lower in the "cavitated" vesicles. Our results suggest that the mode of cell lysis and membrane preparation influence receptor-cyclase interactions and that receptor-cyclase uncoupling is associated with amplified GTP activation and altered receptor regulation by GTP.
Additional Information
© 1984 by American Association of Immunologists. Received for publication October 6. 1983. Accepted for publication November 23. 1983. This work was supported by Grant 17 from the Department of Education and Research, Southern California Permanente Medical Group, and in part by a Biomedical Research Support Grant RR 05521-19 from the Kaiser Foundation Research Institute, and National Institutes of Health Grant Al-16732 (M. Klempner). Publication No. 71 from the Kaiser Regional Research Laboratory. Recipient of Grant AM 30878 from the National Institutes of Health and a grant from the American Heart Associations (GLA). We thank Aline Alenty for advice and assistance in the preparation of neutrophils and in neutrophil function tests. We are also grateful to Lilia Guerrero and Lauren Rosenthal for secretarial assistance. The costs of publication of this article were defrayed In part by the payment of page charges. This article must therefore be hereby marked advertisement In accordance with 18 U.S.C. Section 1734 solely to indicate this fact.Additional details
- Eprint ID
- 57092
- Resolver ID
- CaltechAUTHORS:20150429-130345352
- 17
- Department of Education and Research
- Southern California Permanente Medical Group
- RR 05521-19
- Kaiser Foundation Research Institute
- Al-16732
- NIH
- AM 30878
- NIH
- American Heart Association
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2015-05-01Created from EPrint's datestamp field
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2019-10-03Created from EPrint's last_modified field