AKAP7gamma is a nuclear RI-binding AKAP.
Spatial regulation of protein kinase A (PKA) is accomplished by its sequestration via A-kinase anchor proteins (AKAPs). PKA activity is critical for mammalian oocyte development, suggesting that PKA must be appropriately positioned in these large cells. A screen for AKAPs in oocytes identified AKAP7gamma, an AKAP originally found in pancreas. Yeast two-hybrid analysis and co-immunoprecipitation studies showed that AKAP7gamma bound the type I PKA regulatory subunit (RI) and that the RI-binding domain overlapped the previously identified type II PKA regulatory subunit (RII) binding domain. Overexpressed AKAP7gamma localized to the nuclei of HEK 293 cells via a nuclear localization signal. In addition, endogenous AKAP7gamma protein was found in both the nucleus and cytoplasm of oocytes. This work identifies AKAP7gamma as the first nuclear AKAP to bind RI and suggests that AKAP7gamma may be responsible for positioning PKA via RI and/or RII to regulate PKA-mediated gene transcription in both somatic cells and oocytes.
Brown
Rebecca L
RL
Center for Research on Reproduction and Women's Health, Department of Obstetrics and Gynecology, University of Pennsylvania, Rm. 1312 BRB II/III, 421 Curie Blvd., Philadelphia, PA 19104-6142, USA.
August
Shelley L
SL
Williams
Carmen J
CJ
Moss
Stuart B
SB
D054758:A Kinase Anchor Proteins; D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D002874:Chromosome Mapping; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D005260:Female; D015723:Gene Library; D006801:Humans; D015151:Immunoblotting; D008565:Membrane Proteins; D051379:Mice; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D020798:Two-Hybrid System Techniques
D054758:A Kinase Anchor Proteins; C112596:AKAP7 protein, human; D048868:Adaptor Proteins, Signal Transducing; C487791:Akap7 protein, mouse; D002352:Carrier Proteins; D018076:DNA, Complementary; D008565:Membrane Proteins; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases