Suzuki T, Matozaki T, Mizoguchi A, Kasuga M
Second Department of Internal Medicine, Kobe University School of Medicine, Japan.
Biochem Biophys Res Commun. 1995 Jun 26;211(3):950-9. doi: 10.1006/bbrc.1995.1904.
SH-PTP2 is a protein-tyrosine phosphatase with src homology-2 (SH2) domains and shown to be highly expressed in the rat brain. Light microscopic immunohistochemistry showed that specific immunoreactivity was widely distributed, most abundant in neurophil, weak in neuronal somata, and absent from white matter. By electron microscopic immunohistochemistry, intense labeling is observed on synapses and concentrated in the pre- and post-synaptic plasma membranes. In subcellular fractionation analysis of brain, SH-PTP2 was mainly observed in the particulate fraction, particularly in myelin and synaptosomes. SH-PTP2 was further recovered in the synaptic plasma membrane. SH-PTP2 was extracted from brain membrane with a detergent such as Triton X-100 or Nonidet P-40 but not with 1 M NaCl. Furthermore, SH-PTP2 was coimmunoprecipitated with a 100 kDa tyrosine-phosphorylated membrane protein, which may couple SH-PTP2 to brain membranes. These results suggest that SH-PTP2 associates with synaptic membranes and may play a role in the synaptic communications in the brain.
SH-PTP2是一种具有src同源结构域2（SH2）的蛋白酪氨酸磷酸酶，在大鼠脑中高度表达。光学显微镜免疫组织化学显示，特异性免疫反应广泛分布，在神经纤维中最为丰富，在神经元胞体中较弱，在白质中不存在。通过电子显微镜免疫组织化学观察到，在突触上有强烈的标记，并集中在突触前和突触后的质膜上。在脑的亚细胞分级分离分析中，SH-PTP2主要存在于颗粒部分，特别是在髓磷脂和突触体中。SH-PTP2在突触质膜中进一步回收。用Triton X-100或Nonidet P-40等去污剂可从脑膜中提取SH-PTP2，但用1 M NaCl则不能。此外，SH-PTP2与一种100 kDa的酪氨酸磷酸化膜蛋白共免疫沉淀，该蛋白可能将SH-PTP2与脑膜连接起来。这些结果表明，SH-PTP2与突触膜相关联，可能在脑的突触通讯中发挥作用。
