[Roles of G-protein beta and gamma subunits in the interaction of G beta gamma with adenylyl cyclases II].
OBJECTIVE
To explore the individual roles of G protein beta and gamma subunit in the interactions with effectors.


METHODS
We investigated the interactions of G beta 1 and G beta 1 gamma 2 with adenylyl cyclase II(AC II) using the yeast two-hybrid and three-hybrid systems.


RESULTS
When assayed for the abilities to activate the reporter gene, the interactions among AD-beta 1, gamma 2 and BD-AC IIQ in the three-hybrid system were more potent than the interactions between AD-beta 1 and BD-AC II Q in the two-hybrid system. The expressions of BD-AC IIQ and AD-beta 1 in transformants coexpressed AD-beta 1 and BD-AC IIQ, and transformants coexpressed AD-beta 1, gamma 2 and BD-AC IIQ were respectively detected. The comparisons between the reporter activity and the expression levels of BD-AC IIQ and AD-beta 1 in the yeast cells show there was no correlations, i.e. The difference in the reporter activity was not a reflection of differential expression level of the hybrid proteins.


CONCLUSIONS
All these results suggest that G protein beta 1 subunit is sufficient to maintain the basic interaction between G beta 1 gamma 2 and AC IIQ, and gamma 2 subunit plays an important role in the high affinity interaction of G beta 1 gamma 2 with AC IIQ.
Li
J J
JJ
National Labortary of Medical Molecular Biology, Institute of Basic Medicine Sciences, CAMS, PUMC, Beijing 100005, China.
Lu
N
N
Huang
B R
BR
D000262:Adenylyl Cyclases / Q000378:metabolism*; D044387:GTP-Binding Protein beta Subunits / Q000502:physiology*; D044388:GTP-Binding Protein gamma Subunits / Q000502:physiology*; D020798:Two-Hybrid System Techniques; D015003:Yeasts / Q000235:genetics
D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; D000262:Adenylyl Cyclases; C100622:adenylyl cyclase 2