TY - JOUR
T1 - Phospholipase C-β3 and -β1 form homodimers, but not heterodimers, through catalytic and carboxyl-terminal domains
AU - Zhang, Yong
AU - Vogel, Walter K.
AU - McCullar, Jennifer S.
AU - Greenwood, Jeffrey A.
AU - Filtz, Theresa M.
PY - 2006
Y1 - 2006
N2 - 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.
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.
UR - http://www.scopus.com/inward/record.url?scp=33747603007&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33747603007&partnerID=8YFLogxK
U2 - 10.1124/mol.105.021923
DO - 10.1124/mol.105.021923
M3 - Article
C2 - 16763092
AN - SCOPUS:33747603007
SN - 0026-895X
VL - 70
SP - 860
EP - 868
JO - Molecular Pharmacology
JF - Molecular Pharmacology
IS - 3
ER -