[Effect of EGF on ubiquitination and proteasome-dependent degradation of phospholipase C gamma1 in A431 cells].
Phospholipase C gamma 1 (PLC gamma 1), an enzyme participating in phosphoinositide turnover, is one of the key elements in cell signaling. Here it is shown that treatment of A431 carcinoma cells with proteasome inhibitors Mg132 and lactacystin results in increasing the PLC gamma 1 intracellular level. Simultaneously, several additional bands with lower electrophoretic mobilities were detected on immunoblots, using anti-PLC gamma 1 antibodies. PLC gamma 1 ubiquitinilation was shown using immunoprecepitation. In control A 431 cells, PLC gamma 1 is ubiquitinilated, but the addition of EGF greatly induces the ubiquitinilation of the protein. Association of PLC gamma 1 with ubiquitin-ligase c-Cb1 was shown. Dynamics of ubiquitinilation under EGF treatment is in a close agreement with that of association of PLC gamma 1 and c-Cb1. It is concluded that PLC gamma 1 is ubiquitinilated and degraded by proteasomes. PLC gamma 1 ubiquitinilation is an EGF-dependent process.
Evdonin
A L
AL
Institute of Cytology RAS, St. Petersburg. evdonin@mail.ru
Tsupkina
N V
NV
Nikol'skiĭ
N N
NN
Medvedeva
N D
ND
D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002294:Carcinoma, Squamous Cell / Q000378:metabolism; D045744:Cell Line, Tumor; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000378:metabolism*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology; D009097:Multienzyme Complexes / Q000378:metabolism*; D051966:Phospholipase C gamma; D046988:Proteasome Endopeptidase Complex; D010738:Type C Phospholipases / Q000378:metabolism*; D014452:Ubiquitins / Q000378:metabolism*
D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D009097:Multienzyme Complexes; D014452:Ubiquitins; C067713:lactacystin; D004815:Epidermal Growth Factor; D010738:Type C Phospholipases; D051966:Phospholipase C gamma; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde; D000111:Acetylcysteine