T-type calcium channel trigger p21ras signaling pathway to ERK in Cav3.1-expressed HEK293 cells

We constructed a new cell line which stably expressed Ca(v)3.1 and Kir2.1 subunits in HEK293 cells (HEK293/Ca(v)3.1/Kir2.1) in order to investigate the unknown cellular signaling pathways of T-type voltage-dependent calcium channels. The new cell line has a stable resting membrane potential and can activate T-type Ca2+ channels by KCI-mediated depolarization. We showed that Ca(v)3.1 activation resulted in the level of p21(ras)-GTP in the cells being rapidly decreased during the first 2 min, and then recovering between 2 min and 15 min. The kinetics of ERK activation following Ca(v)3.1 stimulation was also investigated. ERK activation was decreased from 2 min to 5 min after KCl stimulation, which means that Ca(v)3.1 activation reduced ERK activity in the very early stages of activation. In addition, similar results for Ca(v)3.1 activation were also shown in the case of Sos1, Grb2, and Shc, which means that Ca(v)3.1 activation triggers p21(ras) and that this signal is transferred to ERK by Sos1, Grb2, and She. (c) 2005 Elsevier B.V. All rights reserved.