Biber J, Malmström K, Scalera V, Murer H
Pflugers Arch. 1983 Aug;398(3):221-6. doi: 10.1007/BF00657155.
A possible correlation between cyclic-AMP dependent protein phosphorylation and altered sodium dependent transport of inorganic phosphate was analyzed in isolated rat renal proximal tubular brush border membrane vesicles. In transiently opened vesicles (opened by an osmotic shock), the addition of gamma-32P-ATP leads to 32P-incorporation into several membrane proteins. The simultaneous addition of cyclic-AMP leads to increased phosphorylation of several proteins (e.g. apparent molecular weights: 40 kD, 46 kD, 55 kD). The addition of ATP, GTP and ITP to the osmotic shock medium leads to an (non-specific) inhibition of the sodium gradient dependent phosphate uptake. No further inhibition of the sodium dependent phosphate transport was observed when membrane vesicles were phosphorylated by ATP in the presence of cyclic-AMP. These data show a lack of correlation between cyclic-AMP dependent protein phosphorylation and altered sodium gradient dependent phosphate transport. Thus, there is no experimental support for the involvement of cyclic-AMP dependent protein phosphorylation as one of the final events in the regulation of phosphate transport across the rat renal proximal tubular brush border membrane.
在分离的大鼠肾近端小管刷状缘膜囊泡中，分析了环磷酸腺苷（cAMP）依赖性蛋白磷酸化与无机磷酸盐钠依赖性转运改变之间的可能相关性。在短暂开放的囊泡（通过渗透压休克打开）中，添加γ-32P-ATP会导致32P掺入几种膜蛋白中。同时添加环磷酸腺苷会导致几种蛋白质的磷酸化增加（例如，表观分子量：40 kD、46 kD、55 kD）。向渗透压休克培养基中添加ATP、GTP和ITP会导致对钠梯度依赖性磷酸盐摄取的（非特异性）抑制。当膜囊泡在环磷酸腺苷存在下被ATP磷酸化时，未观察到对钠依赖性磷酸盐转运的进一步抑制。这些数据表明cAMP依赖性蛋白磷酸化与钠梯度依赖性磷酸盐转运改变之间缺乏相关性。因此，没有实验支持cAMP依赖性蛋白磷酸化作为大鼠肾近端小管刷状缘膜磷酸盐转运调节的最终事件之一。
