Ohto Tatsuyuki, Uchida Hiroshi, Yamazaki Hiroshi, Keino-Masu Kazuko, Matsui Akira, Masu Masayuki
Department of Molecular Neurobiology, Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
Genes Cells. 2002 Feb;7(2):173-85. doi: 10.1046/j.1356-9597.2001.00502.x.
Sulphated glycosaminoglycans (GAGs) attached to proteoglycan core proteins are implicated in cell adhesion, motility and morphogenesis. Variable sulphation patterns, which are thought to be important for regulating proteoglycan function, are generated by sequential reactions during GAG biosynthesis. However, the mechanism by which such diversity is generated remains unclear.
A novel sulphatase, designated RsulfFP1, was isolated from rat embryos by screening for floor plate specific genes. RsulfFP1 and its orthologues show homology with other sulphatases, and have a distinctive hydrophilic insertion. In situ hybridization showed that RsulfFP1 mRNA is strongly expressed in the floor plate, choroid plexus and cartilage in rat embryos. In vitro transfection experiments revealed that the RsulfFP1 protein is localized to the Golgi apparatus and endoplasmic reticulum, and is not present in the lysosomes. It also appears to be localized on the cell surface.
RsulfFP1, a phylogenetically conserved sulphatase, forms a novel subgroup in the sulphatase family. It shows homology with the lysosomal sulphatases involved in GAG degradation. Localization of the RsulfFP1 protein in the Golgi apparatus and on the cell surface, however, suggests that it may play a role in regulating proteoglycan-mediated signalling by the desulphation of GAGs during biosynthesis or after GAGs are presented in the extracellular space.
附着于蛋白聚糖核心蛋白的硫酸化糖胺聚糖（GAGs）与细胞黏附、运动及形态发生有关。GAG生物合成过程中的系列反应产生了可变的硫酸化模式，这被认为对调节蛋白聚糖功能很重要。然而，这种多样性产生的机制仍不清楚。
通过筛选底板特异性基因，从大鼠胚胎中分离出一种新型硫酸酯酶，命名为RsulfFP1。RsulfFP1及其直系同源物与其他硫酸酯酶显示出同源性，并有一个独特的亲水性插入序列。原位杂交显示，RsulfFP1 mRNA在大鼠胚胎的底板、脉络丛和软骨中强烈表达。体外转染实验表明，RsulfFP1蛋白定位于高尔基体和内质网，不存在于溶酶体中。它似乎也定位于细胞表面。
RsulfFP1是一种系统发育上保守的硫酸酯酶，在硫酸酯酶家族中形成一个新的亚组。它与参与GAG降解的溶酶体硫酸酯酶显示出同源性。然而，RsulfFP1蛋白在高尔基体和细胞表面的定位表明，它可能在生物合成过程中或GAGs出现在细胞外空间后，通过GAGs的去硫酸化作用，在调节蛋白聚糖介导的信号传导中发挥作用。
