Regulation of adenylate cyclase in electropermeabilized Dictyostelium discoideum cells

In Dictyostelium discoideum cells the enzyme adenylate cyclase is functionally coupled to cell surface receptors for cAMP. Coupling is known to involve one or more G-proteins. Receptor-mediated activation of adenylate cyclase is subject to adaptation. In this study we employ an electropermeabilized cell system to investigate regulation of D. discoideum adenylate cyclase. Conditions for selective permeabilization of the plasma membrane have been described by C.D. Schoen, J. C. Arents, T. Bruin, and R. Van Driel (1989, Exp. Cell Res. 181, 51-62). Only small pores are created in the membrane, allowing exchange of exclusively low molecular weight substances like nucleotides, and preventing the loss of macromolecules. Under these conditions functional protein-protein interactions are likely to remain intact. Adenylate cyclase in permeabilized cells was activated by the cAMP receptor agonist 2'-deoxy cAMP and by the nonhydrolyzable GTP-analogue GTP gamma S, which activates G-proteins. The time course of the adenylate cyclase reaction in permeabilized cells was similar to that of intact cells. Maximal adenylate cyclase activity was observed if cAMP receptor agonist or GTP-analogue was added just before cell permeabilization. If these activators were added after permeabilization adenylate cyclase was stimulated in a suboptimal way. The sensitivity of adenylate cyclase activity for receptor occupation was found to decay more rapidly than that for G-protein activation. Importantly, the adenylate cyclase reaction in permeabilized cells was subject to an adaptation-like process that was characterized by a time course similar to adaptation in vivo. In vitro adaptation was not affected by cAMP receptor agonists or by G-protein activation. Evidently electropermeabilized cells constitute an excellent system for investigating the positive and negative regulation of D. discoideum adenylate cyclase.

Medienart:

Artikel

Erscheinungsjahr:

1992

Erschienen:

1992

Enthalten in:

Zur Gesamtaufnahme - volume:199

Enthalten in:

Experimental cell research - 199(1992), 1 vom: 01. März, Seite 162-8

Sprache:

Englisch

Beteiligte Personen:

Schoen, C D [VerfasserIn]
Bruin, T [VerfasserIn]
Arents, J C [VerfasserIn]
van Driel, R [VerfasserIn]

Themen:

1157-33-1
2'-deoxy cyclic AMP
37589-80-3
8L70Q75FXE
Adenosine Triphosphate
Adenylyl Cyclases
Cyclic AMP
E0399OZS9N
EC 3.6.1.-
EC 4.6.1.1
GTP-Binding Proteins
Guanosine 5'-O-(3-Thiotriphosphate)
Journal Article
Receptors, Cyclic AMP
Research Support, Non-U.S. Gov't

Anmerkungen:

Date Completed 10.03.1992

Date Revised 07.07.2019

published: Print

Citation Status MEDLINE

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM012914657