PT  - JOURNAL ARTICLE
AU  - Yong Zhang
AU  - Walter K. Vogel
AU  - Jennifer S. McCullar
AU  - Jeffrey A. Greenwood
AU  - Theresa M. Filtz
TI  - Phospholipase C-β3 and -β1 Form Homodimers, but Not Heterodimers, through Catalytic and Carboxyl-Terminal Domains
AID  - 10.1124/mol.105.021923
DP  - 2006 Sep 01
TA  - Molecular Pharmacology
PG  - 860--868
VI  - 70
IP  - 3
4099  - http://molpharm.aspetjournals.org/content/70/3/860.short
4100  - http://molpharm.aspetjournals.org/content/70/3/860.full
SO  - Mol Pharmacol2006 Sep 01; 70
AB  - Phospholipase C-β (PLC-β) isoenzymes are key effectors in G protein-coupled signaling pathways. Prior research suggests that some isoforms of PLC-β may exist and function as dimers. Using coimmunoprecipitation assays of differentially tagged PLC-β constructs and size-exclusion chromatography of native PLC-β, we observed homodimerization of PLC-β3 and PLC-β1 isoenzymes but failed to detect heterodimerization of these isoenzymes. Size-exclusion chromatography data suggest that PLC-β3 and PLC-β1 form higher affinity homodimers than PLC-β2. Evidence supportive of limited PLC-β monomer-homodimer equilibrium appears at ≤100 nM. Further assessment of homodimerization status by coimmunoprecipitation assays with differentially tagged PLC-β3 fragments demonstrated that at least two subdomains of PLC-β3 are involved in dimer formation, one in the catalytic X and Y domains and the other in the G protein-regulated carboxyl-terminal domain. In addition, we provide evidence consistent with the existence of PLC-β homodimers in a whole-cell context, using fluorescent protein-tagged constructs and microscopic fluorescence resonance energy transfer assays. The American Society for Pharmacology and Experimental Therapeutics