Evidence that phospholipase delta1 is the effector in the Gh (transglutaminase II)-mediated signaling.
A new class of GTP-binding protein transglutaminase II (Gh) couples to a 69-kDa phospholipase C (PLC). An 8-amino acid region (Leu665-Lys672) of the alpha-subunit of Gh (Galphah) is involved in interaction and activation of PLC, an observation that has now been used to characterize the 69-kDa PLC further. A 20-amino acid peptide corresponding to Leu654-Leu673 of Galphah was used to prepare an affinity resin. On incubation with a partially purified PLC preparation from rat liver membranes, the affinity resin-bound approximately69- and 85-kDa proteins were recognized by an antibody to the 69-kDa PLC. Both purified 69-kDa PLC and PLC-delta1 bound to the affinity resin; moreover, antibodies to PLC-delta1 recognized the 69-kDa PLC, and antibodies to the 69-kDa PLC recognized PLC-delta1. A synthetic peptide corresponding to Leu661-Lys672 of Galphah inhibited the binding of PLC-delta1 to the affinity resin and also stimulated PLC-delta1. Reconstitution of PLC-delta1 with GTPgammaS (guanosine 5'-3-O-(thio)triphosphate)-activated Gh resulted in activation of PLC-delta1. Antibodies to Galphah also coimmunoprecipitated PLC-delta1 upon activation of Gh. These findings indicate that PLC-delta1 is the effector of Gh-mediated signaling.
Feng
J F
JF
Department of Molecular Cardiology, Research Institute, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Rhee
S G
SG
Im
M J
MJ
D000595:Amino Acid Sequence; D000818:Animals; D004789:Enzyme Activation; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D008099:Liver / Q000201:enzymology; D008969:Molecular Sequence Data; D054803:Phospholipase C delta; D051381:Rats; D015398:Signal Transduction; D011503:Transglutaminases / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism*
D007527:Isoenzymes; D011503:Transglutaminases; D010738:Type C Phospholipases; C518024:PLCD1 protein, human; D054803:Phospholipase C delta; C518026:Plcd1 protein, rat; D019204:GTP-Binding Proteins