Calmodulin is a phospholipase C-beta interacting protein.
Phospholipase C-beta 3 (PLC beta 3) is an important effector enzyme in G protein-coupled signaling pathways. Activation of PLC beta 3 by G alpha and G beta gamma subunits has been fairly well characterized, but little is known about other protein interactions that may also regulate PLC beta 3 function. A yeast two-hybrid screen of a mouse brain cDNA library with the amino terminus of PLC beta 3 has yielded potential PLC beta 3 interacting proteins including calmodulin (CaM). Physical interaction between CaM and PLC beta 3 is supported by a positive secondary screen in yeast and the identification of a CaM binding site in the amino terminus of PLC beta 3. Co-precipitation of in vitro translated and transcribed amino- and carboxyl-terminal PLC beta 3 revealed CaM binding at a putative amino-terminal binding site. Direct physical interaction of PLC beta 3 and PLC beta 1 isoforms with CaM is supported by pull-down of both isoenzymes with CaM-Sepharose beads from 1321N1 cell lysates. CaM inhibitors reduced M1-muscarinic receptor stimulation of inositol phospholipid hydrolysis in 1321N1 astrocytoma cells consistent with a physiologic role for CaM in modulation of PLC beta activity. There was no effect of CaM kinase II inhibitors, KN-93 and KN-62, on M1-muscarinic receptor stimulation of inositol phosphate hydrolysis, consistent with a direct interaction between PLC beta isoforms and CaM.
McCullar
Jennifer S
JS
Department of Pharmaceutical Sciences, College of Pharmacy, and the Molecular and Cellular Biology Program, Oregon State University, Corvallis, Oregon 97331, USA.
Larsen
Shana A
SA
Millimaki
Ryan A
RA
Filtz
Theresa M
TM
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002147:Calmodulin / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D002217:Carbachol / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D015723:Gene Library; D006801:Humans; D006868:Hydrolysis; D007295:Inositol Phosphates / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D054799:Phospholipase C beta; D011233:Precipitin Tests; D011485:Protein Binding; D014176:Protein Biosynthesis; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D012685:Sepharose / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013347:Subcellular Fractions / Q000378:metabolism; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured; D020798:Two-Hybrid System Techniques; D010738:Type C Phospholipases / Q000378:metabolism*; D001616:beta-Galactosidase / Q000378:metabolism
D002147:Calmodulin; D018076:DNA, Complementary; D007295:Inositol Phosphates; D007527:Isoenzymes; D020033:Protein Isoforms; D002217:Carbachol; D012685:Sepharose; D010738:Type C Phospholipases; C518033:PLCB1 protein, human; C518039:PLCB3 protein, human; D054799:Phospholipase C beta; C518034:Plcb1 protein, mouse; C518040:Plcb3 protein, mouse; D001616:beta-Galactosidase