caa a22 4500 477120385 CHVBK 20180405111635.0 cr unu---uuuuu 170330e19961201xx s 000 0 eng 10.1007/BF00229746 doi (NATIONALLICENCE)springer-10.1007/BF00229746 Effect of phorbol 12,13-dibutyrate on ligand binding, enzyme activity and translocation of protein kinase C isoforms in the αT3-1 gonadotrope-derived cell line [Elektronische Daten] [Melanie Johnson, James Simpson, Rory Mitchell] The effect of incubating αT3-1 cells with phorbol 12,13-dibutyrate (PDBu) on the protein kinase C (PKC) isoform content (predominantly α, ɛ and ζ isoforms) was assessed by immunoblotting, enzyme activity assay and [3H]PDBu binding. After exposure to PDBu for 17 h the immunoreactivity detected for both PKC α and PKC ɛ had disappeared from cytosol and had increased slightly in membranes. Immunoreactivity for PKC ζ was present as two bands in cytosol; after PDBu treatment both bands decreased in intensity, the higher molecular weight band more than the lower. The lower molecular weight band corresponded with a component of constitutive PKC activity eluting from DEAE cellulose that was defined by inhibition of basal activity with GF 109203X or H7. Investigation of very short treatment times with PDBu using binding, immunoblot and activity measurements (in the presence/absence of Ca2+) indicated that translocation of PKC α and ɛ was very rapid — detectable by 10 sec, maximal within minutes. Reduction of these isoforms in membranes took much longer, and was not apparent up to 150 min. The immunoblot data for PKC ζ in cytosol showed no detectable effect of PDBu treatment on the low molecular weight band up to 150 min although it was reduced at 17 h. Translocation of the upper band was detectable at 10 sec but this band may have resulted from cross-reaction with other PKC isoforms. The constitutive activity and low molecular weight (‘authentic') PKC ζ immunoreactivity were partially affected after long exposure only, suggesting an action of PDBu on PKC ζ secondary to activation of the other PKC isoforms. An endogenous receptor agonist, luteinising hormone-releasing hormone (LHRH), was also used to assess by immunoblotting, translocation of the PKC isoforms. Although all the isoforms did translocate from cytosol to membrane fractions, they did so with distinctly different time courses: PKC ɛ moved more rapidly than PKC ζ which appeared to translocate more quickly than PKC α. After downregulation of the responsive PKC isoforms with PDBu, the remaining PKC ζ was not translocated by LHRH. (Mol Cell Biochem 165: 65-75, 1996) Kluwer Academic Publishers, 1996 protein kinase C isoforms nationallicence αT3-1 cell nationallicence phorbol 12,13-dibutyrate nationallicence downregulation nationallicence translocation nationallicence luteinising hormone-releasing hormone nationallicence Johnson Melanie MRC Brain Metabolism Unit, University Department of Pharmacology, 1 George Square, EH8 9JZ, Edinburgh, UK aut Simpson James MRC Brain Metabolism Unit, University Department of Pharmacology, 1 George Square, EH8 9JZ, Edinburgh, UK aut Mitchell Rory MRC Brain Metabolism Unit, University Department of Pharmacology, 1 George Square, EH8 9JZ, Edinburgh, UK aut Molecular and Cellular Biochemistry Kluwer Academic Publishers; http://www.wkap.nl 165/1(1996-12-01), 65-75 0300-8177 165:1<65 1996 165 11010 https://doi.org/10.1007/BF00229746 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00229746 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Johnson Melanie MRC Brain Metabolism Unit, University Department of Pharmacology, 1 George Square, EH8 9JZ, Edinburgh, UK aut NATIONALLICENCE 700 1- Simpson James MRC Brain Metabolism Unit, University Department of Pharmacology, 1 George Square, EH8 9JZ, Edinburgh, UK aut NATIONALLICENCE 700 1- Mitchell Rory MRC Brain Metabolism Unit, University Department of Pharmacology, 1 George Square, EH8 9JZ, Edinburgh, UK aut NATIONALLICENCE 773 0- Molecular and Cellular Biochemistry Kluwer Academic Publishers; http://www.wkap.nl 165/1(1996-12-01), 65-75 0300-8177 165:1<65 1996 165 11010 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer