Interaction of βγ subunits of signal transducing G proteins and c-Jun amino terminal kinase (JNK)

다국어 초록 (Multilingual Abstract)

Heterotrimeric guaine nucleotide binding proteins (G prteins) transduce extracellular signals into intracellular responses by coupling receptors and effectors. The activated G proteins regulate the activity of ion channels and enzymes such as adenylate cyclase and phospholipase C, and they also stimulate mitogen activated protein kinase (MAPK)
Pathways activated by receptor tyrosine Kinase stimulated by various growth tormones. Both the alpha and beta-gamma complex of the G protein are involved in the activation of MAPKs. The Gβr mediates activation of extracellular signal-regulated kinase (MAPK/ERK), c-Jun Nterminal kinase/stress activated protein kinase (JNK/SAPK), p38 MAPK.
However, the difference of the MAPK activating capacity of Gβr among beta subunit isoforms is not known yet. Thus we have overexpressed different beta subunits in COS-l cells and the activation of JNK/SAPK and p38 MAPK by ultraviolet irradiation was analyzed. When beta isoforms of the G protein was cotransfected with Gβ2, all the beta isoforms except β3 were overexpressed. Ultraviolet light stimulated JNK/SAPK activity was increased in the COS-l calls expressing β2 and β4 isoforms, but in the cells expressing β1 and β5, The COS-l cells overexpressing β1 and β5 isoforms chowed increase in the ultraviolet light stimulated p38 MAPK activity. Our results demonstrated that each beta subunit has different potential to activate either JNK/SNPK or p38 MAPK, and suggested that all the tested beta isoforms except beta 3 form functional complexes with gamma 2 subunit of G proteins.

목차 (Table of Contents)

• Abstract
• Introduction
• Materials and Methods
• Results and Discussion
• References