ACTIVATION OF SINGLE-CHANNEL CURRENTS IN MOUSE FIBROBLASTS BY PLATELET-DERIVED GROWTH-FACTOR
ACTIVATION OF SINGLE-CHANNEL CURRENTS IN MOUSE FIBROBLASTS BY PLATELET-DERIVED GROWTH-FACTOR
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DOI：
10.1073/pnas.86.7.2511
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发表时间：
1989-04-01
影响因子：
11.1
通讯作者：
GARGUS, JJ
中科院分区：
文献类型：
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作者：
FRACE, AM;GARGUS, JJ
我们在小鼠l -细胞膜中描述了一种非选择性阳离子通道，它在血清剥夺（细胞生长受阻）时处于静止状态，在血清或血小板衍生生长因子（PDGF）补充时迅速活跃。利用膜片钳技术，我们发现LMTK-细胞系的主要通道是一个破裂的非选择性阳离子通道（NS通道）。在细胞连接和由内到外的贴片中，通道的电导为28ps；对Na+、K+和Cs+具有相同的选择性；没有阴离子或二价阳离子的渗透性。通道打开概率是电压不敏感的，内外斑块与细胞内钙（0.5 nM至50 μ m）无关。当培养物在无血清培养基中孵育而处于静止状态时，与0.26（+-）相比，通道打开概率几乎为0。0.17)。如果有丝分裂是通过将血清注入静止细胞而启动的，同时保持细胞附着的记录，则通道会快速（15-30秒）激活（n = 12）。斑块打开概率增加（> 0.75）2-3 min后减小。我们尝试了几种生长因子（成纤维细胞衍生生长因子、表皮生长因子、胰岛素、bombesin、α）的应用。-凝血酶和抗利尿激素，单独或联合)，但发现只有PDGF （5-100 ng/ml; n = 9）产生通道激活。这种活化应该提供与Na/H交换器平行的Na+进入途径。
A nonselective cation channel that we characterized in the mouse L-cell membrane becomes quiescent with serum deprivation (arrested cell growth) and rapidly active upon readdition of serum or, specifically, platelet-derived growth factor (PDGF). Using the patch-clamp technique, we found that the predominant channel in the LMTK- cell line is a bursting nonselective cation channel (the NS channel). In cell-attached and inside-out patches, the channel has a conductance of 28 pS; equal selectivity for Na+, K+, and Cs+; and no anion or divalent cation permeability. The channel open probability is voltage insensitive and in inside-out patches does not correlate with intracellular calcium (0.5 nM to 50 .mu.M). When cultures are rendered quiescent by incubation in serum-free medium, channel open probability is virtually 0 as compared to 0.26 (.+-. 0.17) in exponentially growing cultures. If mitogenesis is initiated by readdition of serum to quiescent cells while maintaining cell-attached recording, there is a rapid (15-30 s) activation of the channel (n = 12). The open probability of the patch increases (> 0.75) for 2-3 min and then decreases. We have attempted applications of several growth factors (fibroblast-derived growth factor, epidermal growth factor, insulin, bombesin, .alpha.-thrombin, and vasopressin, individually or in combination) but find that only PDGF (5-100 ng/ml; n = 9) produces channel activation. This activation should provide a Na+ entry pathway parallel to that of the Na/H exchanger.