The interaction of nucleoside diphosphate kinase B with Gbetagamma dimers controls heterotrimeric G protein function.
Heterotrimeric G proteins in physiological and pathological processes have been extensively studied so far. However, little is known about mechanisms regulating the cellular content and compartmentalization of G proteins. Here, we show that the association of nucleoside diphosphate kinase B (NDPK B) with the G protein betagamma dimer (Gbetagamma) is required for G protein function in vivo. In zebrafish embryos, morpholino-mediated knockdown of zebrafish NDPK B, but not NDPK A, results in a severe decrease in cardiac contractility. The depletion of NDPK B is associated with a drastic reduction in Gbeta(1)gamma(2) dimer expression. Moreover, the protein levels of the adenylyl cyclase (AC)-regulating Galpha(s) and Galpha(i) subunits as well as the caveolae scaffold proteins caveolin-1 and -3 are strongly reduced. In addition, the knockdown of the zebrafish Gbeta(1) orthologs, Gbeta(1) and Gbeta(1like), causes a cardiac phenotype very similar to that of NDPK B morphants. The loss of Gbeta(1)/Gbeta(1like) is associated with a down-regulation in caveolins, AC-regulating Galpha-subunits, and most important, NDPK B. A comparison of embryonic fibroblasts from wild-type and NDPK A/B knockout mice demonstrate a similar reduction of G protein, caveolin-1 and basal cAMP content in mammalian cells that can be rescued by re-expression of human NDPK B. Thus, our results suggest a role for the interaction of NDPK B with Gbetagamma dimers and caveolins in regulating membranous G protein content and maintaining normal G protein function in vivo.
Hippe
Hans-Joerg
HJ
Department of Internal Medicine III, University of Heidelberg, INF 410, D-69120 Heidelberg, Germany.
Wolf
Nadine M
NM
Abu-Taha
Issam
I
Mehringer
Rebecca
R
Just
Steffen
S
Lutz
Susanne
S
Niroomand
Feraydoon
F
Postel
Edith H
EH
Katus
Hugo A
HA
Rottbauer
Wolfgang
W
Wieland
Thomas
T
D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D044387:GTP-Binding Protein beta Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D044388:GTP-Binding Protein gamma Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D015151:Immunoblotting; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D009200:Myocardial Contraction / Q000235:genetics / Q000502:physiology; D009206:Myocardium / Q000378:metabolism; D054778:NM23 Nucleoside Diphosphate Kinases / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D015027:Zebrafish / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
C118981:G-protein Beta gamma; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; D054778:NM23 Nucleoside Diphosphate Kinases; D029961:Zebrafish Proteins; D000242:Cyclic AMP; C517939:Nme1 protein, mouse; D020962:Heterotrimeric GTP-Binding Proteins