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Mammalian adenylate cyclases are predicted to possess complex topologies, comprising two cassettes of six trans-membrane-spanningmotifs followedbyacytosolic, catalytic ATP-binding domain. Recent studies have begun to provide insights on the tertiary assembly of these proteins; crystal-lographic analysis has revealed that the two cytosolic domains dimerize to forma catalytic core, whilemore recent biochemical and cell biological analysis shows that the two transmembrane cassettes also associate to facilitate the functional assembly and tra ckingof the enzyme. . | Eur. J. Biochem. 269 413-421 2002 FEBS 2002 PRIORITY PAPER Dimerization of mammalian adenylate cyclases Functional biochemical and fluorescence resonance energy transfer FRET studies Chen Gu1 James J. Cali2 and Dermot M. F. Cooper1 3 1Neuroscience Program University of Colorado Health Sciences Center Denver CO USA 2Promega Corp. Madison WI USA 3Department of Pharmacology University of Colorado Health Sciences Center Denver CO USA Mammalian adenylate cyclases are predicted to possess complex topologies comprising two cassettes of six transmembrane-spanning motifs followed by a cytosolic catalytic ATP-binding domain. Recent studies have begun to provide insights on the tertiary assembly of these proteins crystallographic analysis has revealed that the two cytosolic domains dimerize to form a catalytic core while more recent biochemical and cell biological analysis shows that the two transmembrane cassettes also associate to facilitate the functional assembly and trafficking of the enzyme. The older literature had suggested that adenylate cyclases might form higher order aggregates although the methods used did not necessarily provide convincing evidence of biologically relevant events. In the present study we have pursued this question by a variety of approaches including rescue or suppression of function by variously modi ed molecules coimmunoprecipitation and fluorescence resonance energy transfer FRET analysis between molecules in living cells. The results strongly suggest that adenylate cyclases dimerize or oligomerize via their hydrophobic domains. It is speculated that this divalent property may allow adenylate cyclases to participate in multimeric signaling assemblies. Keywords adenylate cyclase dimerization fluorescence resonance energy transfer green fluorescent protein immunoprecipitation. The interjection of stimulatory and inhibitory G-protein modules between receptors and effector increased the complexity of the adenylate cyclase signaling system while .
