Concanavalin A- or phorbol ester-induced translocation of protein kinase C in thymoma cells from a patient with myasthenia gravis.
We have examined the localization of phospholipid/calcium-dependent protein kinase (protein kinase C) in thymoma cells, which were resected from a patient with myasthenia gravis. Upon stimulation with 4 micrograms/ml of concanavalin A (Con A) for 30 min, protein kinase C activity in the cytosolic fraction was increased from 7.44 pmol/min per 10(7) cells to 11.42 pmol/min per 10(7) cells. On the other hand, membrane-associated protein kinase C activity was decreased from 1.69 to 0.71 pmol/min per 10(7) cells. On the contrary, 10(-7) mol/l tetradecanoyl phorbol acetate (TPA) decreased cytosolic protein kinase C activity from 9.31 to 8.04 pmol/min per 10(7) cells, while membrane-associated protein kinase C activity was increased from 1.69 to 2.94 pmol/min per 10(7) cells. Several endogenous phosphorylated proteins (mol wt 20,000, 23,000) were observed as inferred by SDS-polyacrylamide gel electrophoresis. These findings indicated that Con A and TPA produce differential translocation of protein kinase C.
Ishizuka
T
T
Third Department of Internal Medicine, Gifu University School of Medicine, Tsukasamachi, Japan.
Ito
Y
Y
Mori
H
H
Miura
K
K
Nagao
S
S
Nagata
K
K
Nozawa
Y
Y
D003208:Concanavalin A / Q000494:pharmacology*; D003600:Cytosol / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000378:metabolism*; D010703:Phorbol Esters / Q000494:pharmacology*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism; D013945:Thymoma / Q000378:metabolism* / Q000648:ultrastructure; D013953:Thymus Neoplasms / Q000378:metabolism* / Q000648:ultrastructure
D010703:Phorbol Esters; D003208:Concanavalin A; D011493:Protein Kinase C