Jans D A, Hemmings B A
Max-Planck-Institut für Biophysik, Frankfurt am Main, Germany.
FEBS Lett. 1991 Apr 9;281(1-2):267-71. doi: 10.1016/0014-5793(91)80408-u.
The relationship between activation of the cAMP-dependent protein kinase (cAMP-PK) and ligand binding and internalization by the vasopressin renal (V2-type) receptor of LLC-PK1 renal epithelial cells was examined. Upon cAMP-PK activation through 1 h treatment with the cAMP analogue 8-bromo-cAMP (BrcA), a marked reduction in V2-receptor steady state number and internalization in LLC-PK1 cells was effected. In cells treated for 17 h with BrcA and hence down-regulated for cAMP-PK, the V2-receptor number was normal but internalization was markedly reduced. Cells of the LLC-PK1 mutant FIB4, which possesses about 10% parental cAMP-PK catalytic subunit activity, exhibited lower V2-receptor steady state number and internalization in comparison to untreated LLC-PK1 cells. A negative correlation was thus evident between cAMP-PK activation and V2-receptor number, and internalization. Phosphorylation by cAMP-PK may effect ligand-independent removal of receptor from the plasma membrane.
研究了环磷酸腺苷依赖性蛋白激酶（cAMP-PK）的激活与LLC-PK1肾上皮细胞血管加压素肾（V2型）受体的配体结合及内化之间的关系。在用环磷酸腺苷类似物8-溴环磷酸腺苷（BrcA）处理1小时激活cAMP-PK后，LLC-PK1细胞中V2受体的稳态数量和内化明显减少。在用BrcA处理17小时从而使cAMP-PK下调的细胞中，V2受体数量正常，但内化明显减少。LLC-PK1突变体FIB4细胞具有约10%的亲代cAMP-PK催化亚基活性，与未处理的LLC-PK1细胞相比，其V2受体稳态数量和内化较低。因此，cAMP-PK激活与V2受体数量及内化之间存在明显的负相关。cAMP-PK介导的磷酸化可能导致受体从质膜上非配体依赖性去除。
