Freeman R M, Plutzky J, Neel B G
Committee on Virology, Harvard University, Boston, MA 02115.
Proc Natl Acad Sci U S A. 1992 Dec 1;89(23):11239-43. doi: 10.1073/pnas.89.23.11239.
src homology 2 (SH2) domains direct binding to specific phosphotyrosyl proteins. Recently, SH2-containing protein-tyrosine-phosphatases (PTPs) were identified. Using degenerate oligonucleotides and the PCR, we have cloned a cDNA for an additional PTP, SH-PTP2, which contains two SH2 domains and is expressed ubiquitously. When expressed in Escherichia coli, SH-PTP2 displays tyrosine-specific phosphatase activity. Strong sequence similarity between SH-PTP2 and the Drosophila gene corkscrew (csw) and their similar patterns of expression suggest that SH-PTP2 is the human corkscrew homolog. Sequence comparisons between SH-PTP2, SH-PTP1, corkscrew, and other SH2-containing proteins suggest the existence of a subfamily of SH2 domains found specifically in PTPs, whereas comparison of the PTP domains of the SH2-containing PTPs with other tyrosine phosphatases suggests the existence of a subfamily of PTPs containing SH2 domains. Since corkscrew, a member of the terminal class signal transduction pathway, acts in concert with D-raf to positively transduce the signal generated by the receptor tyrosine kinase torso, these findings suggest several mechanisms by which SH-PTP2 may participate in mammalian signal transduction.
src同源结构域2（SH2）可直接与特定的磷酸化酪氨酸蛋白结合。最近，含SH2的蛋白酪氨酸磷酸酶（PTP）被鉴定出来。利用简并寡核苷酸和聚合酶链反应（PCR），我们克隆了另一种PTP的cDNA，即SH-PTP2，它含有两个SH2结构域且在全身广泛表达。当在大肠杆菌中表达时，SH-PTP2表现出酪氨酸特异性磷酸酶活性。SH-PTP2与果蝇基因“螺旋”（csw）之间强烈的序列相似性以及它们相似的表达模式表明，SH-PTP2是人类“螺旋”的同源物。SH-PTP2、SH-PTP1、“螺旋”以及其他含SH2蛋白之间的序列比较表明，存在一个专门存在于PTP中的SH2结构域亚家族；而含SH2的PTP的PTP结构域与其他酪氨酸磷酸酶的比较则表明，存在一个含SH2结构域的PTP亚家族。由于“螺旋”作为终末类信号转导途径的一员，与D-raf协同作用以正向转导受体酪氨酸激酶torso产生的信号，这些发现提示了SH-PTP2可能参与哺乳动物信号转导的几种机制。
