Phosphodiesterase 4D and protein kinase a type II constitute a signaling unit in the centrosomal area.
The mediation of cAMP effects by specific pools of protein kinase A (PKA) targeted to distinct subcellular domains raises the question of how inactivation of the cAMP signal is achieved locally and whether similar targeting of phosphodiesterases (PDEs) to sites of cAMP/PKA action could be observed. Here, we demonstrate that Sertoli cells of the testis contain an insoluble PDE4D3 isoform, which is shown by immunofluorescence to target to centrosomes. Staining of PDE4D and PKA shows co-localization of PDE4D with PKA-RIIalpha and RIIbeta in the centrosomal region. Co-precipitation of RII subunits and PDE4D3 from cytoskeletal extracts indicates a physical association of the two proteins. Distribution of PDE4D overlaps with that of the centrosomal PKA-anchoring protein, AKAP450, and AKAP450, PDE4D3, and PKA-RIIalpha co-immunoprecipitate. Finally, both PDE4D3 and PKA co-precipitate with a soluble fragment of AKAP450 encompassing amino acids 1710 to 2872 when co-expressed in 293T cells. Thus, a centrosomal complex that includes PDE4D and PKA constitutes a novel signaling unit that may provide accurate spatio-temporal modulation of cAMP signals.
Taskén
K A
KA
Institute of Medical Biochemistry, University of Oslo, N-0317 Oslo, Norway.
Collas
P
P
Kemmner
W A
WA
Witczak
O
O
Conti
M
M
Taskén
K
K
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D002503:Centromere; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D006801:Humans; D008297:Male; D051381:Rats; D012708:Sertoli Cells / Q000201:enzymology; D015398:Signal Transduction
D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; C517376:PDE4D protein, human