Permeation and inhibition of polycystin-L channel by monovalent organic cations

被引:11
作者
Dai, Xiao-Qing [1 ]
Karpinski, Edward [1 ]
Chen, Xing-Zhen [1 ]
机构
[1] Univ Alberta, Dept Physiol, Membrane Prot Res Grp, Edmonton, AB T6G 2H7, Canada
来源
BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES | 2006年 / 1758卷 / 02期
基金
加拿大健康研究院; 加拿大创新基金会;
关键词
patch clamp; voltage clamp; Xenopus oocyte; polycystic kidney disease; pore size; organic amine; tetra-alkylammonium;
D O I
10.1016/j.bbamem.2006.01.020
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Polycystin-L (PCL), homologous to polycystin-2 (71% similarity in protein sequence), is the third member of the polycystin family of proteins. Polycystin-1 and -2 are mutated in autosomal dominant polycystic kidney disease, but the physiological role of PCL has not been determined. PCL acts as a Ca-regulated non-selective cation channel permeable to mono- and divalent cations. To further understand the biophysical and pharmacological properties of PCL, we examined a series of organic cations for permeation and inhibition, using single-channel patch clamp and whole-cell two-microelectrode voltage clamp techniques in conjunction with Xenopits oocyte expression. We found that PCL is permeable to organic amines, methlyamine (MA, 3.8 angstrom), dimethylamine (DMA, 4.6 angstrom) and triethylamine (TriEA, 6 angstrom), and to tetra-alkylammonium cation (TAA) tetra-methylanunonium (TMA, 5.5-6.4 angstrom). TAA compounds tetra-ethylammonium (TEA, 6.1-8.2 angstrom) and tetra-propylammoinium (TPA, 9.8 angstrom) were impermeable through PCL and exhibited weak inhibition on PCL (IC50 values > 13 mM). Larger TAA cations tetra-butylammonium (TBA, 11.6 angstrom) and tetra-pentylammonium (TPeA, 13.2 angstrom) were impermeable through PCL as well and showed strong inhibition (IC50 values of 2.7 mM and 1.3 mu M, respectively). Inhibition by TBA was on decreasing the single-channel current amplitude and exhibited no effect on open probability (NPo) or mean open time (MOT), suggesting that it blocks the PCL permeation pathway. In contract, TEA, TPA and TPeA reduced NPo and MOT values but had no effect on the amplitude, suggesting their binding to a different site in PCL, which affects the channel gating. Taken together, our studies revealed that PCL is permeable to organic amines and TAA cation TMA, and that inhibition of PCL by large TAA cations exhibits two different mechanisms, presumably through binding either to the pore pathway to reduce permeant flux or to another site to regulate the channel gating. These data allow to estimate a channel pore size of similar to 7 angstrom for PCL. (c) 2006 Elsevier B.V. All rights reserved.
引用
收藏
页码:197 / 205
页数:9
相关论文
共 27 条
[1]   Organic cation permeation through the channel formed by polycystin-2 [J].
Anyatonwu, GI ;
Ehrlich, BE .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2005, 280 (33) :29488-29493
[2]   Methanethiosulfonate ethylammonium block of amine currents through the ryanodine receptor reveals single pore architecture [J].
Anyatonwu, GI ;
Buck, ED ;
Ehrlich, BE .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2003, 278 (46) :45528-45538
[3]  
Basora N, 2002, J AM SOC NEPHROL, V13, P293, DOI 10.1681/ASN.V132293
[4]   DIFFUSION LIMITATION IN THE BLOCK BY SYMMETRICAL TETRAALKYLAMMONIUM IONS OF ANTHRAX TOXIN CHANNELS IN PLANAR PHOSPHOLIPID-BILAYER MEMBRANES [J].
BLAUSTEIN, RO ;
FINKELSTEIN, A .
JOURNAL OF GENERAL PHYSIOLOGY, 1990, 96 (05) :943-957
[5]   Differences in apparent pore sizes of low and high voltage-activated Ca2+ channels [J].
Cataldi, M ;
Perez-Reyes, E ;
Tsien, RW .
JOURNAL OF BIOLOGICAL CHEMISTRY, 2002, 277 (48) :45969-45976
[6]   Polycystin-L is a calcium-regulated cation channel permeable to calcium ions [J].
Chen, XZ ;
Vassilev, PM ;
Basora, N ;
Peng, JB ;
Nomura, H ;
Segal, Y ;
Brown, EM ;
Reeders, ST ;
Hediger, MA ;
Zhou, J .
NATURE, 1999, 401 (6751) :383-386
[7]   TRP channels as cellular sensors [J].
Clapham, DE .
NATURE, 2003, 426 (6966) :517-524
[8]   Blocker protection in the pore of a voltage-gated K+ channel and its structural implications [J].
del Camino, D ;
Holmgren, M ;
Liu, Y ;
Yellen, G .
NATURE, 2000, 403 (6767) :321-325
[9]   The open pore conformation of potassium channels [J].
Jiang, YX ;
Lee, A ;
Chen, JY ;
Cadene, M ;
Chait, BT ;
MacKinnon, R .
NATURE, 2002, 417 (6888) :523-526
[10]   KIDNEY AND RETINAL DEFECTS (KRD), A TRANSGENE-INDUCED MUTATION WITH A DELETION OF MOUSE CHROMOSOME-19 THAT INCLUDES THE PAX2 LOCUS [J].
KELLER, SA ;
JONES, JM ;
BOYLE, A ;
BARROW, LL ;
KILLEN, PD ;
GREEN, DG ;
KAPOUSTA, NV ;
HITCHCOCK, PF ;
SWANK, RT ;
MEISLER, MH .
GENOMICS, 1994, 23 (02) :309-320