Schwab Albrecht, Wulf Andrea, Schulz Christoph, Kessler Wolfram, Nechyporuk-Zloy Volodymyr, Römer Michael, Reinhardt Jürgen, Weinhold Dietmar, Dieterich Peter, Stock Christian, Hebert Steven C
Institute of Physiology II, Universität Münster, Münster, Germany.
J Cell Physiol. 2006 Jan;206(1):86-94. doi: 10.1002/jcp.20434.
Cell migration is crucial for wound healing, immune defense, or formation of tumor metastases. In addition to the cytoskeleton, Ca2+ sensitive K+ channels (IK1) are also part of the cellular "migration machinery." We showed that Ca2+ sensitive K+ channels support the retraction of the rear part of migrating MDCK-F cells by inducing a localized shrinkage at this cell pole. So far the molecular nature and in particular the subcellular distribution of these channels in MDCK-F cells is unknown. We compared the effect of IK1 channel blockers and activators on the current of a cloned IK1 channel from MDCK-F cells (cIK1) and the migratory behavior of these cells. Using IK1 channels labeled with a HA-tag or the enhanced green fluorescent protein we studied the subcellular distribution of the canine (cIK1) and the human (hIK1) channel protein in different migrating cells. The functional impact of cIK1 channel activity at the front or rear part of MDCK-F cells was assessed with a local superfusion technique and a detailed morphometric analysis. We show that it is cIK1 whose activity is required for migration of MDCK-F cells. IK1 channels are found in the entire plasma membrane, but they are concentrated at the cell front. This is in part due to membrane ruffling at this cell pole. However, there appears to be only little cIK1 channel activity at the front of MDCK-F cells. In our view this apparent discrepancy can be explained by differential regulation of IK1 channels at the front and rear part of migrating cells.
细胞迁移对于伤口愈合、免疫防御或肿瘤转移的形成至关重要。除细胞骨架外，钙敏感钾通道（IK1）也是细胞“迁移机制”的一部分。我们发现钙敏感钾通道通过诱导迁移的MDCK-F细胞尾部局部收缩来支持其尾部回缩。到目前为止，这些通道在MDCK-F细胞中的分子性质，尤其是亚细胞分布尚不清楚。我们比较了IK1通道阻滞剂和激活剂对来自MDCK-F细胞的克隆IK1通道（cIK1）电流以及这些细胞迁移行为的影响。使用用HA标签或增强型绿色荧光蛋白标记的IK1通道，我们研究了犬类（cIK1）和人类（hIK1）通道蛋白在不同迁移细胞中的亚细胞分布。通过局部灌注技术和详细的形态计量分析评估了cIK1通道活性在MDCK-F细胞前部或后部的功能影响。我们表明，MDCK-F细胞迁移需要cIK1的活性。IK1通道存在于整个质膜中，但它们集中在细胞前端。这部分是由于该细胞极处的膜褶皱。然而，在MDCK-F细胞前端似乎只有很少的cIK1通道活性。我们认为，这种明显的差异可以通过迁移细胞前部和后部IK1通道的差异调节来解释。
