Studies of the cAMP mediated aggregation in Dictyostelium discoideum: receptor mediated activation of the adenylate cyclase
Dictyostelium discoideum, a eukaryotic amoeba of the cellular slime mold family, provides an interesting paradigm in developmental biology. During development, hundreds of thousands of cells aggregate to form a multicellular aggregate. Aggregation is mediated by chemotaxis and chemical signaling. Waves of adenosine 3'-5' cyclic monophosphate (cAMP) propagate through the monolayer and provide transient gradients for chemotaxis. The author has used a reversible inhibitor of the cAMP signaling response to demonstrate that adaptation to cAMP is independent of the activation of the adenylate cyclase and therefore is not caused by the rise in intracellular cAMP. Next, it is shown that adenosine inhibits the cAMP signaling response. Inhibition is rapid, reversible, and depends on the cAMP stimulus concentration. Then the specificity of the cAMP receptors which mediates signaling is determined and compared with the receptors which mediate chemotaxis, the cGMP response, and cAMP binding antagonism. The cAMP surface receptor has been identified by photoaffinity labeling intact cells with (/sup 32/P)-8-N/sub 3/-cAMP using an ammonium sulfate binding stabilization technique. The photoactivated ligand specifically labels a polypeptide, localized to the membrane fraction, which migrates as a closely spaced doublet on SDS Page.
- Research Organization:
- Johns Hopkins Univ., Baltimore, MD (USA)
- OSTI ID:
- 6068103
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
550601 -- Medicine-- Unsealed Radionuclides in Diagnostics
59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
ACID ANHYDRASES
AGGLOMERATION
AMOEBA
AMP
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
DAYS LIVING RADIOISOTOPES
ENZYME INDUCTION
ENZYMES
GENE REGULATION
HYDROLASES
INVERTEBRATES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MICROORGANISMS
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PEPTIDES
PHOSPHOHYDROLASES
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
POLYPEPTIDES
PROTEINS
PROTOZOA
RADIOISOTOPES
RADIORECEPTOR ASSAY
SARCODINA
TRACER TECHNIQUES