L. Wang et al., Cloning and mitochondrial localization of full-length D-AKAP2, a protein kinase A anchoring protein, P NAS US, 98(6), 2001, pp. 3220-3225
Citations number
50
Categorie Soggetti
Multidisciplinary
Journal title
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Differential compartmentalization of signaling molecules in cells and tissu
es is being recognized as an important mechanism for regulating the specifi
city of signal transduction pathways. A kinase anchoring proteins (AKAPs) d
irect the subcellular localization of protein kinase A (PKA) by binding to
its regulatory (R) subunits. Dual specific AKAPs (D-AKAPs) interact with bo
th 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
(RCS) domain was previously identified by means of a yeast two-hybrid scre
en. Here, we report: the cloning of full-length human D-AKAP2 (662 residues
) with an additional putative RCS domain, and the corresponding mouse prote
in less the first two exons (617 residues). Expression of D-AKAP2 was chara
cterized by using mouse tissue extracts. Full-length D-AKAP2 from various t
issues shows different molecular weights, possibly because of alternative s
plicing or posttranslational modifications. The cloned human gene product h
as a molecular weight similar to one of the prominent mouse proteins. In vi
vo association of D-AKAP2 with PKA in mouse brain was demonstrated by using
cAMP agarose pull-down assay. Subcellular localization for endogenous mous
e, rat, and human D-AKAP2 was determined by immunocytochemistry, immunohist
ochemistry, and tissue fractionation. D-AKAP2 from all three species is hig
hly enriched in mitochondria. The mitochondrial localization and the presen
ce of RGS domains in D-AKAP2 may have important implications for its functi
on in PKA and G protein signal transduction.