Both N- and C-lobes of calmodulin are required for Ca2+-dependent regulations of CaV1.2 Ca2+ channels
| Autor: | Kazuto Yazawa, Masaki Kameyama, Etsuko Minobe, Liying Hao, Dong-Yun Han, Xiao-yan Bai, Hadhimulya Asmara, Feng Guo |
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| Rok vydání: | 2009 |
| Předmět: |
Calcium metabolism
animal structures Patch-Clamp Techniques Voltage-dependent calcium channel Calmodulin Calcium Channels L-Type Guinea Pigs Biophysics Cell Biology Biology Biochemistry Cav1.2 Protein Structure Tertiary biology.protein Animals Humans Ca2 channels Calcium Patch clamp Molecular Biology |
| Zdroj: | Biochemical and biophysical research communications. 391(2) |
| ISSN: | 1090-2104 |
| Popis: | We investigated the concentration- and Ca(2+)-dependent effects of CaM mutants, CaM(12) and CaM(34), in which Ca(2+)-binding to its N- and C-lobes was eliminated, respectively, on the Ca(V)1.2 Ca(2+) channel by inside-out patch clamp in guinea-pig cardiomyocytes. Both CaM(12) and CaM(34) (0.7-10muM) applied with 3mM ATP produced channel activity after "rundown". Concentration-response curves were bell-shaped, similar to that for wild-type CaM. However, there was no obvious leftward shift of the curves by increasing [Ca(2+)], suggesting that both functional lobes of CaM were necessary for the Ca(2+)-dependent shift. However, channel activity induced by the CaM mutants showed Ca(2+)-dependent decrease, implying a Ca(2+) sensor existing besides CaM. These results suggest that both N- and C-lobes of CaM are required for the Ca(2+)-dependent regulations of Ca(V)1.2 Ca(2+) channels. |
| Databáze: | OpenAIRE |
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