Effects of Calneuron I on N-Type Voltage-gated Ca2+ Channel and CaMKIIβ
Date Issued
2014
Date
2014
Author(s)
Kuo, Tai-Yu
Abstract
N-type voltage gated Ca2+ channel (Cav2.2) opens when membrane potential elevates, then the channels will be inactivated by the influxed of Ca2+. Calmodulin (CaM), a protein with four EF-hand Ca2+-binding motifs, is involved in regulating versatile channel activities. Calneuron I (CalnI) is homologous to the calmodulin and belongs to the Ca2+ binding protein family. CalnI is known to control the vesicle trafficking from Golgi to the plasma membrane and our previous results shows that CalnI suppresses the currents of Cav2.2 expressed in 293T cells. However, it is not clear CalnI interacts with Cav2.2. CalnI and Cav2.2 mutations in the IQ motif were co-expressed in 293T cells to examine the effects of CalnI on Ca2+ currents using whole-cell patch clamp technique. The IQ motif at the C-terminal of Cav2.2 is proposed to be the CaM binding site; it is possible that CalnI binds to this motif. Our results showed that CalnI suppressed the Cav2.2 current density with or without mutations in the IQ motif. Using yeast-two-hybrid, my lab has previously shown that CalnI interacts with CaMKIIβ. To confirm this interaction, I used GST-CalnI as the bait and the CaMKIIβ expressed in 293T cells could be pull down. In contrast, GST-CalnI did not pulldown CaMKIIα efficiently. Our results suggest that CalnI may not interact with the Cav2.2 through the conserved IQ motif to suppress the Ca2+ current. By interacting with CaMKIIβ, CalnI may be involved in regulating the syanptic plasticity.
Subjects
Calneuron I
Cav2.2
人類胚腎293細胞
IQ motif
CaMKIIβ
Type
thesis
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