Transition metal chelator TPEN counteracts phorbol ester-induced actin cytoskeletal disruption in C6 rat glioma cells without inhibiting activation or translocation of protein kinase C.

摘要: Phorbol ester–induced reorganization of the actin cytoskeleton was investigated in C6 rat glioma cells. Observations by fluorescence microscopy and photoelectron indicated that pretreatment with transition metal chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) for 1–2 h at 50 μM reduced sensitivity to disruption subsequent addition 200 nM phorbol myristate acetate (PMA). The protective effect TPEN eliminated adding back Zn2+ prior PMA addition, implicating chelation ions as mechanism action TPEN. cells exposed experience potent activation protein kinase C (PKC) substantial redistribution from a soluble particulate cellular fraction (translocation). did not block PKC translocation PMA-exposed By two-dimensional gel analysis, also reduce, but rather slightly increased, PMA-stimulated phosphorylation acidic 80 kDa endogenous substrate, well two other proteins 18 kDa. In contrast, significantly suppressed 20 protein, both treated only TPEN-pretreated results indicate ability protect against PKC-mediated cytoskeletal is due either or general inhibition activity. Rather, more selective probably involves critical -dependent step downstream initial tumor promoter–-induced effects on PKC. © 1994 Wiley-Liss, Inc.