title: Gβγ-mediated activation of protein kinase D exhibits subunit specificity and requires Gβγ-responsive phospholipase Cβ isoforms.
abstract: BACKGROUND
  Protein kinase D (PKD) constitutes a novel family of serine/threonine protein kinases implicated in fundamental biological activities including cell proliferation, survival, migration, and immune responses. Activation of PKD in these cellular activities has been linked to many extracellular signals acting through antigen receptor engagement, receptor tyrosine kinases, as well as G protein-coupled receptors. In the latter case, it is generally believed that the Gα subunits of the Gq family are highly effective in mediating PKD activation, whereas little is known with regard to the ability of Gβγ dimers and other Gα subunits to stimulate PKD. It has been suggested that the interaction between Gβγ and the PH domain of PKD, or the Gβγ-induced PLCβ/PKC activity is critical for the induction of PKD activation. However, the relative contribution of these two apparently independent events to Gβγ-mediated PKD activation has yet to be addressed.
  
  
  RESULTS
  In this report, we demonstrate that among various members in the four G protein families, only the Gα subunits of the Gq family effectively activate all the three PKD isoforms (PKD1/2/3), while Gα subunits of other G protein families (Gs, Gi, and G12) are ineffective. Though the Gα subunits of Gi family are unable to stimulate PKD, receptors linked to Gi proteins are capable of triggering PKD activation in cell lines endogenously expressing (HeLa cells and Jurkat T-cells) or exogenously transfected with (HEK293 cells) Gβγ-sensitive PLCβ2/3 isoforms. This indicates that the Gi-mediated PKD activation is dependent on the released Gβγ dimers upon stimulation. Further investigation on individual Gβγ combinations (i.e. Gβ1 with Gγ1-13) revealed that, even if they can stimulate the PLCβ activity in a comparable manner, only those Gβ1γ dimers with γ2, γ3, γ4, γ5, γ7, and γ10 can serve as effective activators of PKD. We also demonstrated that Gi-mediated PKD activation is essential for the SDF-1α-induced chemotaxis on Jurkat T-cells.
  
  
  CONCLUSIONS
  Our current report illustrates that Gβγ dimers from the Gi proteins may activate PKD in a PLCβ2/3-dependent manner, and the specific identities of Gγ components within Gβγ dimers may determine this stimulatory action.
authors.affiliation: Division of Life Science and the Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong. boyung@ust.hk.
authors.forename: Winnie Wi
authors.initials: WW
authors.lastname: Lau
authors.forename: Anthony Sl
authors.initials: AS
authors.lastname: Chan
authors.forename: Lydia Sw
authors.initials: LS
authors.lastname: Poon
authors.forename: Jing
authors.initials: J
authors.lastname: Zhu
authors.forename: Yung H
authors.initials: YH
authors.lastname: Wong
references.citation: J Biol Chem. 2003 Feb 14;278(7):4882-91
references.pmid: 12477719
references.citation: J Biol Chem. 2008 May 23;283(21):14590-9
references.pmid: 18332134
references.citation: Cell Signal. 2006 Jul;18(7):1051-62
references.pmid: 16198087
references.citation: Neurosignals. 2009;17(1):71-81
references.pmid: 19212141
references.citation: Trends Pharmacol Sci. 2009 Jun;30(6):278-86
references.pmid: 19427041
references.citation: J Biol Chem. 1997 Sep 19;272(38):23952-60
references.pmid: 9295346
references.citation: J Neurochem. 2003 Feb;84(3):503-13
references.pmid: 12558970
references.citation: FEBS Lett. 2007 Sep 4;581(22):4279-87
references.pmid: 17707375
references.citation: Cell Signal. 2012 Apr;24(4):914-21
references.pmid: 22227248
references.citation: J Exp Med. 2000 Jun 19;191(12):2075-82
references.pmid: 10859332
references.citation: J Biol Chem. 2009 Jan 23;284(4):2332-43
references.pmid: 19029298
references.citation: Proc Natl Acad Sci U S A. 2008 Feb 26;105(8):3059-63
references.pmid: 18287012
references.citation: Cell Signal. 1997 May-Jun;9(3-4):207-18
references.pmid: 9218120
references.citation: Biotechnol J. 2012 Jan;7(1):17-8
references.pmid: 22057971
references.citation: Am J Physiol Gastrointest Liver Physiol. 2008 May;294(5):G1245-56
references.pmid: 18308856
references.citation: Biochem Biophys Res Commun. 2006 Sep 29;348(3):945-9
references.pmid: 16899224
references.citation: J Immunol. 1999 Dec 1;163(11):5954-63
references.pmid: 10570282
references.citation: Mol Pharmacol. 2005 Jan;67(1):152-62
references.pmid: 15496505
references.citation: J Biol Chem. 2000 Jan 21;275(3):2157-64
references.pmid: 10636921
references.citation: Biochemistry. 1999 Feb 2;38(5):1488-96
references.pmid: 9931014
references.citation: J Biol Chem. 2000 Mar 17;275(11):7466-9
references.pmid: 10713048
references.citation: J Biol Chem. 1994 Feb 25;269(8):6140-8
references.pmid: 8119958
references.citation: Annu Rev Pharmacol Toxicol. 2009;49:31-56
references.pmid: 18834311
references.citation: Proc Natl Acad Sci U S A. 1994 Aug 30;91(18):8572-6
references.pmid: 8078925
references.citation: Biochem J. 2007 Aug 15;406(1):157-65
references.pmid: 17492941
references.citation: Cell. 1999 Jul 9;98(1):59-68
references.pmid: 10412981
references.citation: Mol Pharmacol. 2006 Mar;69(3):877-87
references.pmid: 16319284
references.citation: J Cell Biol. 2005 Apr 11;169(1):83-91
references.pmid: 15824133
references.citation: J Biol Chem. 2009 Sep 4;284(36):24653-61
references.pmid: 19581308
references.citation: J Biol Chem. 2010 Aug 6;285(32):24805-14
references.pmid: 20525682
references.citation: Annu Rev Biochem. 1987;56:615-49
references.pmid: 3113327
references.citation: J Biol Chem. 2009 Jan 23;284(4):2459-71
references.pmid: 19028687
references.citation: J Biol Chem. 2012 Mar 2;287(10):7121-33
references.pmid: 22207761
references.citation: Cancer Res. 2009 Jul 15;69(14):5634-8
references.pmid: 19567672
references.citation: J Biol Chem. 2001 Oct 19;276(42):38619-27
references.pmid: 11507098
references.citation: J Physiol. 2008 Jul 15;586(14):3325-35
references.pmid: 18499725
references.citation: Mol Cancer Ther. 2012 Jul;11(7):1389-99
references.pmid: 22532599
references.citation: J Biol Chem. 1991 Aug 25;266(24):15595-7
references.pmid: 1908456
references.citation: Int Immunol. 2006 Dec;18(12):1737-47
references.pmid: 17077180
references.citation: J Biol Chem. 2004 Apr 16;279(16):16883-93
references.pmid: 14963034
references.citation: Proc Natl Acad Sci U S A. 2010 Jun 22;107(25):11417-22
references.pmid: 20534534
references.citation: Biochem J. 2010 Nov 15;432(1):153-63
references.pmid: 20819079
references.citation: J Biol Chem. 2002 Dec 13;277(50):48427-33
references.pmid: 12376552
references.citation: J Biol Chem. 1995 Jan 20;270(3):1455-61
references.pmid: 7836415
references.citation: EMBO J. 2003 Jan 2;22(1):109-20
references.pmid: 12505989
references.citation: Arterioscler Thromb Vasc Biol. 2009 Sep;29(9):1376-82
references.pmid: 19520973
references.citation: Biochim Biophys Acta. 2010 Dec;1806(2):183-92
references.pmid: 20580776
references.citation: Cell Signal. 2010 Jul;22(7):1153-61
references.pmid: 20227493
references.citation: J Biol Chem. 1998 Jan 2;273(1):410-6
references.pmid: 9417097
references.citation: Physiology (Bethesda). 2011 Feb;26(1):23-33
references.pmid: 21357900
references.citation: Biochem Biophys Res Commun. 2003 Apr 11;303(3):920-5
references.pmid: 12670499
references.citation: Adv Enzyme Regul. 2011;51(1):138-51
references.pmid: 21035486
references.citation: Br J Pharmacol. 2001 Apr;132(7):1431-40
references.pmid: 11264236
references.citation: J Biol Chem. 2003 Feb 21;278(8):6575-9
references.pmid: 12488442
references.citation: Cell Mol Life Sci. 2008 Jul;65(14):2191-214
references.pmid: 18488142
references.citation: J Biol Chem. 2009 Jan 9;284(2):799-806
references.pmid: 19001381
references.citation: Cell Signal. 2009 May;21(5):737-44
references.pmid: 19168127
references.citation: Int J Biochem Cell Biol. 2010 Jun;42(6):1052-9
references.pmid: 20348012
references.citation: Mol Cell Biol. 2004 Sep;24(17):7758-68
references.pmid: 15314181
references.citation: FEBS Lett. 2003 Jul 3;546(1):81-6
references.pmid: 12829240