Identification of a functional Gs protein in Euglena gracilis.
We found a Gs protein coupled to adenylyl cyclase in a free-living protist, Euglena gracilis. This Gs protein of approximately 42 kDa is substrate for cholera toxin and is recognized by an antibody against the C-terminal decapeptide of Gs. Furthermore, this protein is coupled to adenylyl cyclase, as shown by: (a) the activation of the enzyme by GTP-analogues and (b) the effect of cholera toxin on cAMP accumulation in intact cells and the continuous activation of adenylyl cyclase activity in membranes. These data indicate that the Gs-adenylyl cyclase-coupled system is already apparent in the protist kingdom.
Torres-Márquez
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ME
Departamento de Bioquímica, Instituto Nacional de Cardiologia Ignacio Chávez, México, D.F., México.
Macías-Silva
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M
Vega-Segura
A
A
D000246:Adenosine Diphosphate Ribose / Q000737:chemistry; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002458:Cell Fractionation; D002478:Cells, Cultured; D002772:Cholera Toxin / Q000633:toxicity*; D000242:Cyclic AMP / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005055:Euglena / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D008970:Molecular Weight; D011233:Precipitin Tests; D015398:Signal Transduction / Q000187:drug effects
D000246:Adenosine Diphosphate Ribose; D006160:Guanosine Triphosphate; D002772:Cholera Toxin; D000242:Cyclic AMP; D019205:GTP-Binding Protein alpha Subunits, Gs; D000262:Adenylyl Cyclases