Ethanol differently affects stress protein and HERG K+ channel expression in SH-SY5Y cells

Ethanol is known to be neurotoxic. Protective mechanisms, however, are activated upon ethanol induction of the glucose-regulated stress proteins (GRPs), GRP78 and GRP94. These endoplasmic reticulum-residing chaperones are known to be involved in channel subunit assembly, The GRP and human-ether-a-gogo-related gene (HERG) K+-channel expression were monitored in short- and long-term ethanol incubation experiments using the human neuroblastoma cell line SH-SY5Y mRNA of the stress proteins and protein levels of the GRPs and HERG were determined using Northern and Western blot methods. Short-term ethanol incubation caused a transient increase of GRP transcripts. Protein levels of GRP94 decreased in chronic experiments, whereas GRP78 did not change. HERG followed the same kinetics as GRP94 with a constant down-regulation. The coordinate down-regulation of GRP94 and HERG implies the specific involvement of the endoplasmic reticulum chaperone GRP94 and HERG, but not GRP78, in a process of cell adaptation, (C) 2002 Elsevier Science B.V. All rights reserved.