Hindered diffusion through an aqueous pore describes invariant dye selectivity of Cx43 junctions
Hindered diffusion through an aqueous pore describes invariant dye selectivity of Cx43 junctions
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DOI：
10.1529/biophysj.107.115634
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发表时间：
2008-02-01
影响因子：
3.4
通讯作者：
Burt, Janis M.
中科院分区：
文献类型：
--
作者：
Heyman, Nathanael S.;Burt, Janis M.
缝隙连接的选择透过性（渗透/电导）是连接功能的可变参数。为了确定连接选择性渗透性的这种变化是否是由包含通道的异质电荷或大小选择性解释的，在四种细胞类型中确定了单个Cx43间隙连接对大小或电荷不同的两种染料的组合的渗透性：Rin 43，NRKe，HeLa 43和心肌细胞。结果表明，Cx43结是尺寸选择性的，但不是电荷选择性的，这两个选择性是结函数的常数参数。染料选择性的一致性表明，测得的交界处的选择性渗透率的大连续不能归因于一个等效的连续的个别通道的选择性。此外，NBD-M-TMA的相对染料渗透性顺序类似于Alexa 350 >荧光黄> Alexa 488 >> Alexa 594（斯托克斯半径为4.3（A）在圆上，4.4（A）在圆上，4.9（A）在圆上，5.8（A）在圆上，和7.4（A）在圆上，和类似于谷氨酸钾的KCl > TEACl的电导序列通过半径类似于10和长度160（A）的圆形水孔的受阻扩散很好地描述。的选择渗透性和染料选择性数据表明，在Cx43的导电通道，无论是染料不可渗透或染料可渗透的路口的变量存在。
The permselectivity (permeance/conductance) of Cx43-comprised gap junctions is a variable parameter of junctional function. To ascertain whether this variability in junctional permselectivity is explained by heterogeneous charge or size selectivity of the comprising channels, the permeance of individual Cx43 gap junctions to combinations of two dyes differing in either size or charge was determined in four cell types: Rin43, NRKe, HeLa43, and cardiac myocytes. The results show that Cx43 junctions are size-but not charge-selective and that both selectivities are constant parameters of junctional function. The consistency of dye selectivities indicates that the large continuum of measured junctional permselectivities cannot be ascribed to an equivalent continuum of individual channel selectivities. Further, the relative dye permeance sequence of NBD-M-TMA similar to Alexa 350 > Lucifer yellow > Alexa 488 >> Alexa 594 (Stokes radii of 4.3 (A) over circle, 4.4 (A) over circle, 4.9 (A) over circle, 5.8 (A) over circle, and 7.4 (A) over circle, respectively) and the conductance sequence of KCl > TEACl similar to Kglutamate are well described by hindered diffusion through an aqueous pore with radius similar to 10 and length 160 (A) over circle. The permselectivity and dye selectivity data suggest the variable presence in Cx43-comprised junctions of conductive channels that are either dye-impermeable or dye-permeable.