A novel putative protein-tyrosine phosphatase contains a BRO1-like domain and suppresses Ha-ras-mediated transformation
A novel putative protein-tyrosine phosphatase contains a BRO1-like domain and suppresses Ha-ras-mediated transformation
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DOI：
10.1074/jbc.273.33.21077
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发表时间：
1998-08-14
影响因子：
4.8
通讯作者：
Zhou, MD
中科院分区：
文献类型：
--
作者：
Cao, LG;Zhang, L;Zhou, MD
为了研究蛋白酪氨酸磷酸酶（PTPases）在心肌生长和信号传导中的潜在作用，使用基于简并引物的逆转录-聚合酶链反应方法分离含有PTPases催化结构域的蛋白质的cDNA。从新生大鼠心肌细胞总RNA中通过逆转录-聚合酶链反应分离出16个cDNA克隆，其中一个命名为PTP-TD 14，是唯一的。随后的全长PTP-TD 14 cDNA的分离和测序证实，它编码一种新的164-kDa蛋白质，p164（PTP-TD 14）。C-末端区域含有PTP样结构域，而N-末端区域显示与任何已知的哺乳动物蛋白质没有同源性。然而，该区域与参与有丝分裂原活化蛋白激酶信号通路的酵母蛋白BRO 1同源。与BRO 1一样，p164（PTP-TD 14）含有一个富含脯氨酸的区域，该区域具有两个推定的SH 3结构域结合位点。通过北方印迹分析，PTP-TD 14以5.3-磷酸酶对转录本的形式表达，不仅在新生大鼠心脏中，而且在许多成年大鼠组织中也表达。当在COS-7或NIH-3 T3细胞中表达时，p164（PTP-TD 14）定位于与囊泡样结构相关的细胞质。p164（PTP-TD 14）在NIH-3 T3细胞中的表达抑制Ha ras介导的转化超过3倍。这种抑制活性定位于C-末端PTP 14同源结构域，因为用PTP-TD 14突变体没有观察到Ha-ras介导的病灶形成的抑制，其中推定的催化活性可能被点突变灭活。这些发现表明，PTP-TD 14编码一种新的蛋白质，可能是至关重要的参与调节Ha-ras依赖的细胞生长。
To investigate a potential role of protein-tyrosine phosphatases (PTPases) in myocardial growth and signaling, a degenerate primer-based reverse transcription-polymerase chain reaction approach was used to isolate cDNAs for proteins that contain a PTPase catalytic domain. Among the 16 cDNA clones isolated by reverse transcription-polymerase chain reaction from total neonatal rat cardiomyocyte RNA, one, designated PTP-TD14, was unique. Subsequent isolation and sequencing of a full-length PTP-TD14 cDNA confirmed that it encodes a novel 164-kDa protein, p164(PTP-TD14) The C-terminal region contains the PTP-like domain, whereas the N-terminal region shows no homology to any known mammalian protein. However, this region is homologous to a yeast protein, BRO1, that is involved in the mitogen-activated protein kinase signaling pathway. Like BRO1, p164(PTP-TD14) contains a proline-rich region with two putative SH3-domain binding sites. By Northern blot analysis, PTP-TD14 is expressed as a 5.3-kilobase pair transcript, not only in neonatal heart but also in many adult rat tissues. When expressed in either COS-7 or NIH-3T3 cells, p164(PTP-TD14) localizes to the cytoplasm in association with vesicle-like structures. Expression of p164(PTP-TD14) in NIH-3T3 cells inhibits Ha ras-mediated transformation more than 3-fold. This inhibitory activity is localized to the C-terminal PTPase homology domain, since no inhibition of Ha-ras-mediated focus formation was observed with a PTP-TD14 mutant, in which the putative catalytic activity was presumably inactivated by a point mutation. These findings indicate that PTP-TD14 encodes a novel protein that may be critically involved in regulating Ha-ras-dependent cell growth.