Bagshaw Richard D, Callahan John W, Mahuran Don J
Research Institute, The Hospital for Sick Children, Canada M5G1X8.
Biochem Biophys Res Commun. 2006 Jun 16;344(4):1186-91. doi: 10.1016/j.bbrc.2006.03.221. Epub 2006 Apr 19.
Lysosomes are late-endocytic organelles which primarily contribute to degradation and recycling of cellular material. From a previous proteomics study of purified rat liver lysosomal membranes we identified a protein from the Arf-family of small GTPases, Arl8b. Although proteins of the Arf-family have roles in a wide range of cellular functions, most notably roles in protein/vesicular trafficking, Arl8b represents the first from this protein family to be associated with a late-endocytic organelle. We demonstrate the co-localization of this protein with various lysosomal markers in different cell lines by confocal-immunofluorescence microscopy. We also show that GTP-restricted mutant Arl8b localizes to lysosomes and causes their redistribution to the periphery of the cell and into membrane projections. This indicates that Arl8b is involved in trafficking processes for lysosomes.
溶酶体是晚期内吞细胞器，主要参与细胞物质的降解和再循环。通过之前对纯化的大鼠肝脏溶酶体膜进行的蛋白质组学研究，我们从小GTP酶的Arf家族中鉴定出一种蛋白质，即Arl8b。尽管Arf家族的蛋白质在广泛的细胞功能中发挥作用，最显著的是在蛋白质/囊泡运输中发挥作用，但Arl8b是该蛋白质家族中第一个与晚期内吞细胞器相关的成员。我们通过共聚焦免疫荧光显微镜证明了该蛋白质在不同细胞系中与各种溶酶体标记物的共定位。我们还表明，GTP受限的突变型Arl8b定位于溶酶体，并导致它们重新分布到细胞周边和膜突起中。这表明Arl8b参与了溶酶体的运输过程。
