Bush J, Franek K, Daniel J, Spiegelman G B, Weeks G, Cardelli J
Department of Microbiology and Immunology, Louisiana State University Medical Center, Shreveport 71130.
Gene. 1993 Dec 22;136(1-2):55-60. doi: 10.1016/0378-1119(93)90447-b.
Low-M(r) GTPases belonging to the Ras superfamily are known to regulate a wide range of cellular processes including cell proliferation, actin cytoskeleton organization, and vesicular trafficking along the secretory and endosomal/lysosomal pathway. We are studying the regulation of lysosomal and endosomal vesicular trafficking in the simple eukaryote, Dictyostelium discoideum. Using an oligodeoxyribonucleotide (oligo) encoding one of the most highly conserved amino acid (aa) regions found in the low-M(r) GTPases (important in GTP binding), we have cloned 18 new cDNAs encoding proteins belonging to the Ras superfamily. In this report, we describe the characterization of five of these cDNAs coding for proteins belonging to the Ypt1/Sec4/Rab family; mammalian members of this family have been shown to function in the regulation of vesicular trafficking. Two of the cDNAs, rab1A and rab1B, code for proteins highly homologous to mammalian Rab1. An additional cDNA, rabA, codes for a protein that is only 60% identical to Rab1 at the aa sequence level and probably represents a new member of the rab gene family. Finally, two cDNAs, rabB and rabC, code for novel proteins belonging to the Rab gene family that are no greater than 50% identical in aa sequence to any previously described member. Southern blot analysis indicated that rab1A and and rab1B belong to a small Dictyostelium family of at least five related genes, while rabA belongs to a different and smaller family of related genes. In contrast, rabB and rabC appear to be represented by single genes.(ABSTRACT TRUNCATED AT 250 WORDS)
属于Ras超家族的低分子量GTP酶已知可调节广泛的细胞过程，包括细胞增殖、肌动蛋白细胞骨架组织以及沿分泌和内体/溶酶体途径的囊泡运输。我们正在研究简单真核生物盘基网柄菌中溶酶体和内体囊泡运输的调节。使用编码在低分子量GTP酶中发现的最高度保守氨基酸区域之一（对GTP结合很重要）的寡脱氧核糖核苷酸（oligo），我们克隆了18个新的cDNA，它们编码属于Ras超家族的蛋白质。在本报告中，我们描述了其中五个编码属于Ypt1/Sec4/Rab家族蛋白质的cDNA的特征；该家族的哺乳动物成员已被证明在囊泡运输调节中起作用。其中两个cDNA，rabA和rabB，编码与哺乳动物Rab1高度同源的蛋白质。另一个cDNA，rabA，编码一种在氨基酸序列水平上与Rab1只有60%相同的蛋白质，可能代表rab基因家族的一个新成员。最后，两个cDNA，rabB和rabC，编码属于Rab基因家族的新蛋白质，其氨基酸序列与任何先前描述的成员的相同性不超过50%。Southern印迹分析表明，rab1A和rab1B属于一个至少有五个相关基因的小型盘基网柄菌家族，而rabA属于一个不同的、较小的相关基因家族。相比之下，rabB和rabC似乎由单个基因代表。（摘要截断于250字）
