Inhibition of ErbB-2 mitogenic and transforming activity by RALT, a mitogen-induced signal transducer which binds to the ErbB-2 kinase domain
Inhibition of ErbB-2 mitogenic and transforming activity by RALT, a mitogen-induced signal transducer which binds to the ErbB-2 kinase domain
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DOI：
10.1128/mcb.20.20.7735-7750.2000
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发表时间：
2000-10-01
影响因子：
5.3
通讯作者：
Segatto, O
中科院分区：
文献类型：
--
作者：
Fiorentino, L;Pertica, C;Segatto, O
大鼠基因33的产物在双杂交筛选中被鉴定为ErbB-2相互作用蛋白，所述双杂交筛选采用ErbB-2的质膜和激酶结构域作为诱饵。这种相互作用在体外与谷胱甘肽S-转移酶融合蛋白跨越位置282至395的459个残基的基因33蛋白质。ErbB-2催化功能的激活是活细胞中ErbB-2-gene 33物理相互作用所必需的，而ErbB-2自身磷酸化是不必要的。基因33蛋白的表达在生长停滞的NIH 3 T3成纤维细胞中不存在，但在血清刺激或ErbB-2激酶激活的60至90分钟内诱导，并在进入S期后急剧下降。新的分化因子刺激的有丝分裂原剥夺的乳腺上皮细胞也导致积累的基因33蛋白，这可以发现在一个复杂的ErbB-2。小鼠成纤维细胞中基因33蛋白的过表达抑制（i）由ErbB-2而非血清驱动的细胞增殖，（ii）由ErbB-2而非Ras或Src诱导的细胞转化，和（iii）由ErbB-2而非血清持续激活ERK 1和2。基因33蛋白可以通过其与含SH 3的蛋白质（包括GRB-2）的结合向ErbB-2下游传递抑制信号，GRB-2被发现与活细胞中的基因33蛋白结合。这些数据表明，基因33蛋白是ErbB-2促有丝分裂功能的反馈抑制剂和ErbB-2致癌活性的抑制剂。我们建议将基因33蛋白重新命名为RALT（受体相关晚期转导子）。
The product of rat gene 33 was identified as an ErbB-2-interacting protein in a two-hybrid screen employing the ErbB-2 juxtamembrane and kinase domains as bait. This interaction was reproduced in vitro with a glutathione S-transferase fusion protein spanning positions 282 to 395 of the 459-residue gene 33 protein. Activation of ErbB-2 catalytic function was required for ErbB-2-gene 33 physical interaction in living cells, whereas ErbB-2 autophosphorylation was dispensable. Expression of gene 33 protein was absent in growth-arrested NIH 3T3 fibroblasts but was induced within 60 to 90 min of serum stimulation or activation of the ErbB-2 kinase and decreased sharply upon entry into S phase. New differentiation factor stimulation of mitogen-deprived mammary epithelial cells also caused accumulation of gene 33 protein, which could be found in a complex with ErbB-2. Overexpression of gene 33 protein in mouse fibroblasts inhibited (i) cell proliferation driven by ErbB-2 but not by serum, (ii) cell transformation induced by ErbB-2 but not by Ras or Src, and (iii) sustained activation of ERK 1 and 2 by ErbB-2 but not by serum. The gene 33 protein may convey inhibitory signals downstream to ErbB-2 by virtue of its association with SH3-containing proteins, including GRB-2, which was found to associate with gene 33 protein in living cells. These data indicate that the gene 33 protein is a feedback inhibitor of ErbB-2 mitogenic function and a suppressor of ErbB-2 oncogenic activity. We propose that the gene 33 protein be renamed with the acronym RALT (receptor-associated late transducer).