兔红细胞中磷脂酰肌醇周转的成熟依赖性

Maturation dependence of the turnover of phosphatidylinositides in rabbit red blood cells.

作者信息

Maretzki D, Ueta N, Reimann B, Schwarzer E, Kostic M, Rapoport S M

出版信息

Biomed Biochim Acta. 1987;46(2-3):S167-71.

Abstract

"Pulse-chase" experiments with erythrocytes and reticulocytes prelabelled with 32P-Pi revealed a high turnover of the monoester phosphate groups of PIP2 in reticulocytes, which declines strongly during maturation [Maretzki et al., Biomed. Biochim. Acta 45, 1227-1236 (1986)]. The 3H-inositol uptake exhibits a strong maturational loss. A carrier-mediated uptake of inositol in reticulocytes is suggested. In reticulocytes PI, PIP and PIP2 incorporated 3H-inositol in the relative distribution of 86; 5 and 9%, respectively, but only PI to a minor extent in erythrocytes. A small release of 3H-labelled inositol phosphates was found in reticulocytes, which was not stimulated by extracellular calcium during incubation. Determination of the 32P/3H-ratio in double-labelled phosphatidylinositides in reticulocytes demonstrated a very slow turnover of the diester phosphate bonds compared with that of the inositol phosphate ester groups.

摘要

用32P-Pi预标记的红细胞和网织红细胞进行的“脉冲追踪”实验表明，网织红细胞中PIP2的单酯磷酸基团周转迅速，而在成熟过程中周转急剧下降[马雷茨基等人，《生物医学与生物化学学报》45，1227 - 1236(1986)]。3H-肌醇摄取表现出明显的成熟性丧失。提示网织红细胞中存在载体介导的肌醇摄取。在网织红细胞中，PI、PIP和PIP2掺入3H-肌醇的相对比例分别为86%、5%和9%，而在红细胞中只有PI有少量掺入。在网织红细胞中发现有少量3H标记的肌醇磷酸酯释放，孵育期间细胞外钙对此无刺激作用。网织红细胞中双标记磷脂酰肌醇的32P/3H比值测定表明，与肌醇磷酸酯基团相比，二酯磷酸键的周转非常缓慢。