Malide D, Davies-Hill T M, Levine M, Simpson I A
Experimental Diabetes, Metabolism, and Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
Am J Physiol. 1998 Mar;274(3):E516-26. doi: 10.1152/ajpendo.1998.274.3.E516.
We determined subcellular localization of GLUT-1, GLUT-3, and GLUT-5 as human monocytes differentiate into macrophages in culture, and effects of the activating agents N-formyl-methionyl-leucyl-phenylalanine (fMLP) and phorbol myristate acetate (PMA). Western blot analysis demonstrated progressively increased GLUT-1, rapidly decreased GLUT-3, and a delayed increase of GLUT-5 expression during differentiation. Confocal microscopy revealed that each isoform displayed a unique subcellular distribution and cell-activation response. GLUT-1 was localized primarily to the cell surface but was also detected in the perinuclear region in a pattern characteristic of recycling endosomes. GLUT-3 exhibited predominantly a distinct vesicle-like staining but was present only in monocytes. GLUT-5 was found primarily at the cell surface but was detectable intracellularly. Activation with fMLP induced similar GLUT-1 and GLUT-5 redistributions from intracellular compartments toward the cell surface. PMA elicited a similar translocation of GLUT-1, but GLUT-5 was redistributed from the plasma membrane to a distinct intracellular compartment that appeared connected to the cell surface. These results suggest specific subcellular targeting of each transporter isoform and differential regulation of their trafficking pathways in cultured macrophages.
我们确定了在培养过程中人类单核细胞分化为巨噬细胞时葡萄糖转运蛋白1（GLUT-1）、葡萄糖转运蛋白3（GLUT-3）和葡萄糖转运蛋白5（GLUT-5）的亚细胞定位，以及激活剂N-甲酰甲硫氨酰亮氨酰苯丙氨酸（fMLP）和佛波酯（PMA）的作用。蛋白质免疫印迹分析表明，在分化过程中，GLUT-1表达逐渐增加，GLUT-3迅速下降，GLUT-5表达延迟增加。共聚焦显微镜显示，每种异构体都表现出独特的亚细胞分布和细胞激活反应。GLUT-1主要定位于细胞表面，但也以回收内体的特征模式在核周区域被检测到。GLUT-3主要表现为明显的囊泡样染色，但仅存在于单核细胞中。GLUT-5主要在细胞表面被发现，但在细胞内也可检测到。fMLP激活诱导GLUT-1和GLUT-5从细胞内区室向细胞表面发生类似的重新分布。PMA引起GLUT-1类似的易位，但GLUT-5从质膜重新分布到一个明显的细胞内区室，该区域似乎与细胞表面相连。这些结果表明，在培养的巨噬细胞中，每种转运蛋白异构体具有特定的亚细胞靶向定位，并且其运输途径受到不同的调节。
