Gruppuso P A, Boylan J M
Department of Pediatrics, Brown University, Providence, RI.
Second Messengers Phosphoproteins. 1992;14(3):99-108.
We have identified multiple members of the protein tyrosine phosphatase family in three subcellular compartments from rat liver; membrane, cytoskeleton and cytosol. Characterization based on substrate specificity, size, and reactivity with an anti-peptide antiserum against human placental PTP1B indicate the presence of at least three PTPases in Triton X-100 extracts of particulate membranes. Of these, one of 600 kDa possesses characteristics of a transmembrane, receptor-like enzyme. A fourth particulate PTPase (70 kDa) represents a distinct cytoskeletal PTPase. Cytosol contains one main PTPase species which was detected as a 41 kDa protein in Western immunoblots. These data indicate the existence of multiple hepatic PTPases whose differences in structure and subcellular localization may reflect functional heterogeneity.
我们已在大鼠肝脏的三个亚细胞区室（膜、细胞骨架和胞质溶胶）中鉴定出蛋白质酪氨酸磷酸酶家族的多个成员。基于底物特异性、大小以及与针对人胎盘PTP1B的抗肽抗血清的反应性进行的表征表明，在微粒体膜的Triton X-100提取物中至少存在三种蛋白酪氨酸磷酸酶。其中，一种600 kDa的酶具有跨膜、受体样酶的特征。第四种微粒体蛋白酪氨酸磷酸酶（70 kDa）代表一种独特的细胞骨架蛋白酪氨酸磷酸酶。胞质溶胶中含有一种主要的蛋白酪氨酸磷酸酶，在Western免疫印迹中检测为41 kDa的蛋白质。这些数据表明存在多种肝脏蛋白酪氨酸磷酸酶，其结构和亚细胞定位的差异可能反映了功能异质性。
