Abstract
Human ether-a-go-go related-gene K+ channels (hERG) participate in the regulation of tumor cell proliferation and apoptosis. HERG channel activity is up-regulated by growth factors. Kinases sensitive to growth factor signaling include the serine/threonine protein kinase B-RAF. The present study thus explored whether B-RAF influences hERG channel expression and activity. To this end, hERG channels were expressed in Xenopus oocytes with or without wild-type B-RAF, hERG channel activity was determined utilizing dual-electrode voltage clamp and hERG protein abundance in the cell membrane was analyzed utilizing confocal microscopy as well as chemiluminescence. Moreover, in rhabdomyosarcoma RD cells the effect of B-RAF inhibitor PLX-4720 on hERG-mediated current was quantified by whole-cell patch clamp and hERG cell surface protein abundance by utilizing biotinylation of cell surface proteins as well as flow cytometry. As a result, co-expression of wild-type B-RAF in hERG-expressing Xenopus oocytes significantly increased hERG channel activity and hERG channel protein abundance in the cell membrane. Treatment for 24 hours of B-RAF and hERG-expressing Xenopus oocytes with B-RAF inhibitor PLX-4720 (10 µM) significantly decreased hERG-mediated current and hERG cell surface expression. Similarly, in rhabdomyosarcoma RD cells, treatment for 24 hours with B-RAF inhibitor PLX-4720 significantly decreased hERG cell membrane protein abundance and hERG-mediated current. In conclusion, B-RAF is a powerful regulator of hERG channel activity and cell surface hERG protein abundance.
Highlights
Human ether-a-go-go related-gene K+ channels, hERG are expressed strongly in the heart and contribute to the repolarization of cardiomyocytes [1,2,3,4]
The present study explored whether the serine/threonine kinase B-RAF influences the activity of human ether-a-go-go related-gene K+ channels
The present study reveals that the serine/threonine kinase BRAF is a powerful stimulator of the human ether-a-go-go relatedgene K+ channels
Summary
Human ether-a-go-go related-gene K+ channels, hERG (encoded by the KCNH2 gene) are expressed strongly in the heart and contribute to the repolarization of cardiomyocytes [1,2,3,4]. The hERG K+ channels are expressed in a variety of tumor cells and participate in the machinery regulating tumor cell proliferation [5,6,7,8,9], apoptosis [10,11] as well as tumor cell migration [12,13]. HERG K+ channels are up-regulated by and contribute to the signaling of growth factors [17,18,19]. Growth factor signaling involves B-RAF [20], a serine/threonine kinase up-regulated in a variety of tumor cells [21,22,23,24]. The kinase plays a critical role in the activation of the RAS/RAF/MEK/ERK pathway, which participates in the regulation of cell proliferation, differentiation and survival [25]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
