TY - JOUR
T1 - Reciprocal regulation of glutathione S-transferase spliceforms and the Drosophila C-Jun N-terminal kinase pathway components
AU - Udomsinprasert, R.
AU - Bogoyevitch, M.A.
AU - Ketterman, A.J.
PY - 2004
Y1 - 2004
N2 - In mammalian systems, detoxification enzymes of the GST(glutathione S-transferase) family regulate JNK (c-Jun N-terminal kinase) signal transduction by interaction with INK itself or other proteins upstream in the JNK pathway. In the present study, we have studied GSTs and their interaction with components of the JNK pathway from Diptera. We have evaluated the effects of four Delta class Anopheles dirus GSTs, GSTD1-1, GSTD2-2, GSTD3-3 and GSTD4-4, on the activity of full-length recombinant Drosophila HEP (mitogen-activated protein kinase kinase 7; where HEP stands for hemipterous) and the Drosophila JNK, as well as the reciprocal effect of these kinases on GST activity. Interestingly, even though these four GSTs are alternatively spliced products of the same gene and share > 60% identity, they exerted different effects on INK activity. GSTD1-1 inhibited JNK activity, whereas the other three GST isoforms activated JNK. GSTD2-2, GSTD3-3 and GSTD4-4 were inhibited 50-80% by HEP or JNK but GSTD1-1 was not inhibited by INK. However, there were some similarities in the actions of HEP and JNK on these GSTs. For example, binding constants for HEP or JNK inhibiting a GST were similar (20-70 nM). Furthermore, after incubation of the GSTs with JNK, both JNK and the GSTs changed catalytic properties. The substrate specificities of both GSTs and JNK were also altered after their co-incubation. In addition, glutathione modulated the effects of JNK on GST activity. These results emphasize that different GST spliceformus possess different properties, both in their catalytic function and in their regulation of signalling through the JNK pathway.
AB - In mammalian systems, detoxification enzymes of the GST(glutathione S-transferase) family regulate JNK (c-Jun N-terminal kinase) signal transduction by interaction with INK itself or other proteins upstream in the JNK pathway. In the present study, we have studied GSTs and their interaction with components of the JNK pathway from Diptera. We have evaluated the effects of four Delta class Anopheles dirus GSTs, GSTD1-1, GSTD2-2, GSTD3-3 and GSTD4-4, on the activity of full-length recombinant Drosophila HEP (mitogen-activated protein kinase kinase 7; where HEP stands for hemipterous) and the Drosophila JNK, as well as the reciprocal effect of these kinases on GST activity. Interestingly, even though these four GSTs are alternatively spliced products of the same gene and share > 60% identity, they exerted different effects on INK activity. GSTD1-1 inhibited JNK activity, whereas the other three GST isoforms activated JNK. GSTD2-2, GSTD3-3 and GSTD4-4 were inhibited 50-80% by HEP or JNK but GSTD1-1 was not inhibited by INK. However, there were some similarities in the actions of HEP and JNK on these GSTs. For example, binding constants for HEP or JNK inhibiting a GST were similar (20-70 nM). Furthermore, after incubation of the GSTs with JNK, both JNK and the GSTs changed catalytic properties. The substrate specificities of both GSTs and JNK were also altered after their co-incubation. In addition, glutathione modulated the effects of JNK on GST activity. These results emphasize that different GST spliceformus possess different properties, both in their catalytic function and in their regulation of signalling through the JNK pathway.
U2 - 10.1042/BJ20040519
DO - 10.1042/BJ20040519
M3 - Article
VL - 383
SP - 483
EP - 490
JO - The Biochemical journal
JF - The Biochemical journal
SN - 0264-6021
ER -