P碱性成纤维细胞生长因子(bFGF)磷酸化——神经保护作用必要条件之一
德国Münster大学
许多生长因子具有神经保护潜能。然而，生长因子用于治疗脑损伤却不是那么简单，因为其通过血脑屏障的能力有限。所以，本研究是为了探索如何增强内源性生长因子的神经保护性活力。
本研究中，我们有证据表明，bFGF 磷酸化作用本身在缺乏内源性激酶作用时bFGF 磷酸化起到非常关键的作用。这种自我磷酸化作用随酸度而发生变化，提示未涉及丝氨酸、苏氨酸、酪氨酸残基。有文献报道指出，组氨酸残基修饰作用可抑制神经生长因子(NGF)与其受体结合、阻滞bFGF的活性。因此，实施位点定向突变暴露bFGF磷酸化作用位点。值得注意的是，这种bFGF自我磷酸化作用是bFGF神经保护作用的必要条件。bFGF联合碱性磷酸酶不再具有神经保护作用，而bFGF磷酸化后能体现神经保护作用(即使伴有碱性磷酸酶环境下)。
这些结果提示，抑制bFGF(及其他生长因子) 去磷酸化能提高生长因子的神经保护能力。
Phosphorylation of bFGF as a prerequisite for neuroprotection
Susanne Klumpp
University of Münster, Germany
Various growth factors have been shown to possess a neuroprotective potency. However, growth factors cannot easily be used for therapy of brain damage because of their limited permeation through the blood-brain barrier. Therefore, we searched for strategies to increase the neuroprotective activity of endogenous growth factors.
Here we present evidence that upstream phosphorylation of bFGF itself is crucial for its effect. bFGF phosphorylates in the absence of exogenous kinases. This autophosphorylation is acid-labile, indicating that serine-, threonine-or tyrosine residues are not involved. There are reports in the literature stating that modification of histidine residues inhibits binding of NGF to its receptor and blocks bFGF activity. Therefore, site-directed mutagenesis is performed to unravel the phosphorylation site of bFGF. Importantly, such autophosphorylation of bFGF is a prerequisite for its neuroprotective effect. bFGF treated with alkaline phosphatase is no longer protective, whereas persistently phosphorylated bFGF is neuroprotective, despite the presence of alkaline phosphatase.
These results suggest that the inhibition of dephosphorylation of bFGF and probably also of other growth factors could increase their neuroprotective activity., 百拇医药
许多生长因子具有神经保护潜能。然而，生长因子用于治疗脑损伤却不是那么简单，因为其通过血脑屏障的能力有限。所以，本研究是为了探索如何增强内源性生长因子的神经保护性活力。
本研究中，我们有证据表明，bFGF 磷酸化作用本身在缺乏内源性激酶作用时bFGF 磷酸化起到非常关键的作用。这种自我磷酸化作用随酸度而发生变化，提示未涉及丝氨酸、苏氨酸、酪氨酸残基。有文献报道指出，组氨酸残基修饰作用可抑制神经生长因子(NGF)与其受体结合、阻滞bFGF的活性。因此，实施位点定向突变暴露bFGF磷酸化作用位点。值得注意的是，这种bFGF自我磷酸化作用是bFGF神经保护作用的必要条件。bFGF联合碱性磷酸酶不再具有神经保护作用，而bFGF磷酸化后能体现神经保护作用(即使伴有碱性磷酸酶环境下)。
这些结果提示，抑制bFGF(及其他生长因子) 去磷酸化能提高生长因子的神经保护能力。
Phosphorylation of bFGF as a prerequisite for neuroprotection
Susanne Klumpp
University of Münster, Germany
Various growth factors have been shown to possess a neuroprotective potency. However, growth factors cannot easily be used for therapy of brain damage because of their limited permeation through the blood-brain barrier. Therefore, we searched for strategies to increase the neuroprotective activity of endogenous growth factors.
Here we present evidence that upstream phosphorylation of bFGF itself is crucial for its effect. bFGF phosphorylates in the absence of exogenous kinases. This autophosphorylation is acid-labile, indicating that serine-, threonine-or tyrosine residues are not involved. There are reports in the literature stating that modification of histidine residues inhibits binding of NGF to its receptor and blocks bFGF activity. Therefore, site-directed mutagenesis is performed to unravel the phosphorylation site of bFGF. Importantly, such autophosphorylation of bFGF is a prerequisite for its neuroprotective effect. bFGF treated with alkaline phosphatase is no longer protective, whereas persistently phosphorylated bFGF is neuroprotective, despite the presence of alkaline phosphatase.
These results suggest that the inhibition of dephosphorylation of bFGF and probably also of other growth factors could increase their neuroprotective activity., 百拇医药