Colocalization and coassembly of two human brain M-type potassium channel subunits that are mutated in epilepsy

被引:176
作者
Cooper, EC
Aldape, KD
Abosch, A
Barbaro, NM
Berger, MS
Peacock, WS
Jan, YN
Jan, LY
机构
[1] Univ Calif San Francisco, Dept Physiol, San Francisco, CA 94143 USA
[2] Univ Calif San Francisco, Dept Neurol, San Francisco, CA 94143 USA
[3] Univ Calif San Francisco, Dept Pathol, San Francisco, CA 94143 USA
[4] Univ Calif San Francisco, Dept Neurosurg, San Francisco, CA 94143 USA
[5] Univ Calif San Francisco, Dept Biochem, San Francisco, CA 94143 USA
[6] Univ Calif San Francisco, Howard Hughes Med Inst, San Francisco, CA 94143 USA
关键词
D O I
10.1073/pnas.090092797
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Acetylcholine excites many central and autonomic neurons through inhibition of M-channels. slowly activating, noninactivating voltage-gated potassium channels. We here provide information regarding the in vivo distribution and biochemical characteristics of human brain KCNQ2 and KCNQ3, two channel subunits that form M-channels when expressed in vitro, and, when mutated, cause the dominantly inherited epileptic syndrome, benign neonatal familial convulsions. KCNQ2 and KCNQ3 proteins are colocalized in a somatodendritic pattern on pyramidal and polymorphic neurons in the human cortex and hippocampus. Immunoreactivity for KCNQ2, but not KCNQ3, is also prominent in some terminal fields, suggesting a presynaptic role for a distinct subgroup of M-channels in the regulation of action potential propagation and neurotransmitter release. KCNQ2 and KCNQ3 can be coimmunoprecipitated from brain lysates. Further, KCNQ2 and KCNQ3 are coassociated with tubulin and protein kinase A within a Triton X-100-insoluble protein complex. This complex is not associated with low-density membrane rafts or with N-methyl-D-aspartate receptors, PSD-95 scaffolding proteins, or other potassium channels tested. Our studies thus provide a view of a signaling complex that may be important for cognitive function as well as epilepsy. Analysis of this complex may shed light on the unknown transduction pathway linking muscarinic acetylcholine receptor activation to M-channel inhibition.
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收藏
页码:4914 / 4919
页数:6
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