Cloning and mitochondrial localization of full-length D-AKAP2, a protein kinase A anchoring protein.
Differential compartmentalization of signaling molecules in cells and tissues is being recognized as an important mechanism for regulating the specificity of signal transduction pathways. A kinase anchoring proteins (AKAPs) direct the subcellular localization of protein kinase A (PKA) by binding to its regulatory (R) subunits. Dual specific AKAPs (D-AKAPs) interact with both RI and RII. A 372-residue fragment of mouse D-AKAP2 with a 40-residue C-terminal PKA binding region and a putative regulator of G protein signaling (RGS) domain was previously identified by means of a yeast two-hybrid screen. Here, we report the cloning of full-length human D-AKAP2 (662 residues) with an additional putative RGS domain, and the corresponding mouse protein less the first two exons (617 residues). Expression of D-AKAP2 was characterized by using mouse tissue extracts. Full-length D-AKAP2 from various tissues shows different molecular weights, possibly because of alternative splicing or posttranslational modifications. The cloned human gene product has a molecular weight similar to one of the prominent mouse proteins. In vivo association of D-AKAP2 with PKA in mouse brain was demonstrated by using cAMP agarose pull-down assay. Subcellular localization for endogenous mouse, rat, and human D-AKAP2 was determined by immunocytochemistry, immunohistochemistry, and tissue fractionation. D-AKAP2 from all three species is highly enriched in mitochondria. The mitochondrial localization and the presence of RGS domains in D-AKAP2 may have important implications for its function in PKA and G protein signal transduction.
Wang
L
L
Department of Chemistry and Biochemistry, Howard Hughes Medical Institute, University of California at San Diego, La Jolla, CA 92093-0654, USA.
Sunahara
R K
RK
Krumins
A
A
Perkins
G
G
Crochiere
M L
ML
Mackey
M
M
Bell
S
S
Ellisman
M H
MH
Taylor
S S
SS
D054758:A Kinase Anchor Proteins; D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D018076:DNA, Complementary; D006801:Humans; D051379:Mice; D008928:Mitochondria / Q000378:metabolism* / Q000648:ultrastructure; D008969:Molecular Sequence Data; D051381:Rats; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions; D014018:Tissue Distribution
D054758:A Kinase Anchor Proteins; C484639:AKAP10 protein, human; D048868:Adaptor Proteins, Signal Transducing; C108772:Akap10 protein, mouse; D002352:Carrier Proteins; D018076:DNA, Complementary; D017868:Cyclic AMP-Dependent Protein Kinases