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Targeted expression of activated Q227L G(alpha)(s) in vivo.

Authors: Xi-Ping, Huang; Xiaosong, Song; Hsien-Yu, Wang; Craig C, Malbon;

Targeted expression of activated Q227L G(alpha)(s) in vivo.

Abstract

We report the creation of transgenic mice with an inducible, tissue-targeted expression of a constitutively active mutant form (Q227L) of G(alpha)(s). Mice expressing activated G(alpha)(s) in fat tissue, liver, and skeletal muscle displayed normal body mass and blunted glucose metabolism. cAMP accumulation in adipose tissue was increased in the basal state, but far less than would be expected. Marked adaptation to elevated cAMP levels occurred, leading to an increase in total cAMP-specific phosphodiesterase activity, a 50% decline in cAMP-dependent protein kinase (protein kinase A) activity, and an increased expression of G(alpha)(i2). The reduction in kinase activity coincided with >50% increase in the expression of RIalpha and RIIalpha regulatory subunits of protein kinase A, with no change in the amount of catalytic subunit. These data demonstrate the existence of adaptive responses of protein kinase A, phosphodiesterase, and G(alpha)(i2) in tissues expressing constitutively active G(alpha)(s) that may act to rectify the impact of increased cAMP accumulation.

Keywords

Phosphoric Diester Hydrolases, Gene Expression, Mice, Transgenic, GTP-Binding Protein alpha Subunits, Gi-Go, Adaptation, Physiological, Cyclic AMP-Dependent Protein Kinases, Mice, Adipose Tissue, Liver, Proto-Oncogene Proteins, Gene Targeting, Mutation, Cyclic AMP, GTP-Binding Protein alpha Subunits, Gs, Animals, GTP-Binding Protein alpha Subunit, Gi2, Muscle, Skeletal

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citations
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
13
Average
Average
Top 10%