Jiang L W, Maher V M, McCormick J J, Schindler M
Department of Biochemistry, Michigan State University, East Lansing 48824-1316.
J Biol Chem. 1990 Mar 25;265(9):4775-7.
The pH of the intralysosomal compartment of fibroblasts in culture was monitored by measuring the fluorescence emission intensity at 530 nm of fluid phase pinocytosed fluorescein-conjugated dextrans (FITC-dextrans) excited at 488 and 457 nm. Following the procedure of Ohkuma and Poole (Ohkuma, S., and Poole, B. (1978) Proc. Natl. Acad. Sci. U. S. A. (1978) 75, 3327-3331), a relationship was established between the fluorescence emission intensity of the FITC-dextrans and pH. This correlation was used to determine the intralysosomal apparent pH (pHapp) of a series of fibroblast cultures. The mean intralysosomal pHapp values of nontransformed mouse 3T3 fibroblasts and an infinite life-span human fibroblast cell strain, designated MSU-1.1, was 5.0. In distinction that of 3T3 fibroblasts transformed to the malignant state by Kirsten murine sarcoma virus and MSU-1.1 cells transformed by transfection of the v-Ki-ras or T24 H-ras oncogene was 6.1. These measurements suggest that ras transformation results in a significant perturbation of lysosomal pH.
通过测量在488和457nm激发下，液相胞饮的荧光素偶联葡聚糖（FITC-葡聚糖）在530nm处的荧光发射强度，监测培养的成纤维细胞溶酶体内区室的pH值。按照大久保和普尔的方法（大久保，S.，和普尔，B.（1978年）《美国国家科学院院刊》（1978年）75，3327 - 3331），建立了FITC-葡聚糖的荧光发射强度与pH值之间的关系。这种相关性用于确定一系列成纤维细胞培养物的溶酶体内表观pH值（pHapp）。未转化的小鼠3T3成纤维细胞和一种无限寿命的人成纤维细胞系（命名为MSU-1.1）的溶酶体内平均pHapp值为5.0。相比之下，经 Kirsten 鼠肉瘤病毒转化为恶性状态的3T3成纤维细胞以及通过转染v-Ki-ras或T24 H-ras癌基因转化的MSU-1.1细胞的溶酶体内平均pHapp值为6.1。这些测量结果表明，ras转化导致溶酶体pH值发生显著扰动。
