Vol. 47 (2005), N 4, p. 296-310

cAMP-PKA SIGNAL PATHWAY IN THE LOWER EUKARYOTES I. V. Shemarova I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, RAS, St. Petersburg, Russia; e-mail: irina@lis.mail.iephb.ru The review summarizes current data regarding transduction mechanisms by cAMP-PKA signal pathway in unicellular eukaryotes. Conceptions of evolutionary origin of eukaryotic signal transduction systems are developed. Key words:  unicellular eukaryotes, intracellular signaling, cAMP, heterotrimeric G-proteins, proliferation, differentiation, chcmotaxis, PKA, MAP-kinase cascade