The carboxy-terminal hydrophobic domain of TIG3, a class II tumor suppressor protein, is required for appropriate cellular localization and optimal biological activity.
The carboxy-terminal hydrophobic domain of TIG3, a class II tumor suppressor protein, is required for appropriate cellular localization and optimal biological activity.
复制标题
DOI：
10.3892/ijo.17.6.1195
复制
发表时间：
2000-12
影响因子：
5.2
通讯作者：
A. Deucher;S. Nagpal;R. A. Chandraratna;Daniel Di Sepio;N. Robinson;S. Dashti;R. Eckert
中科院分区：
文献类型：
--
作者：
A. Deucher;S. Nagpal;R. A. Chandraratna;Daniel Di Sepio;N. Robinson;S. Dashti;R. Eckert
TIG 3是最近发现的II类肿瘤抑制蛋白，最初从类维生素A处理的培养的表皮角质形成细胞中分离，其抑制多种上皮细胞类型的增殖。在本研究中，我们研究了这种蛋白降低CHO，T47 D和HaCaT细胞增殖的能力，以及羧基末端疏水结构域在这种调节中的作用。全长TIG 3蛋白TIG 31 -164的载体介导的表达导致集落形成效率降低50-70%。缺乏推定的羧基末端膜锚定结构域的截短突变体TIG 31 -134的表达导致抑制集落形成的能力的部分丧失。截短的蛋白质保持部分活性的事实表明，TIG 3的氨基和羧基末端区域都是最佳生长抑制所需的。全长蛋白分布在核周位置，而不存在于核中。相反，TIG 31 -134分布在细胞质中。因此，位置的改变与活动的部分丧失相关联。我们还监测了绿色荧光蛋白（GFP）-TIG 3融合蛋白的分布。GFP-TIG 31 -164的定位模式与TIG 31 -164观察到的模式相似，而GFP-TIG 31 -134则显示出与GFP相似的分布模式。这表明C-末端疏水结构域在决定TIG 3的细胞内定位中具有重要作用。此外，GFP-TIG 31 -164保留了抑制细胞功能的能力，而GFP-TIG 31 -134是无活性的。
TIG3 is a recently discovered class II tumor suppressor protein, originally isolated from retinoid-treated cultured epidermal keratinocytes, that suppresses the proliferation of a variety of epithelial cell types. In the present study, we examine the ability of this protein to reduce CHO, T47D and HaCaT cell proliferation, and the role of the carboxy-terminal hydrophobic domain in this regulation. Vector-mediated expression of the full length TIG3 protein, TIG31-164, results in a 50-70% reduction colony formation efficiency. Expression of a truncated mutant, TIG31-134, that lacks the putative carboxy-terminal membrane-anchoring domain, results in a partial loss of ability to suppress colony formation. The fact that the truncated protein remains partially active suggests that both the amino- and carboxy-terminal regions of TIG3 are required for optimal growth suppression. The full-length protein is distributed in a perinuclear location, and is not present in the nucleus. TIG31-134, in contrast, is distributed in the cytoplasm. Thus, a change in location is associated with the partial loss of activity. We also monitored the distribution of green fluorescent protein (GFP)-TIG3 fusion proteins. GFP-TIG31-164 was localized in a pattern similar to that observed for TIG31-164, while GFP-TIG31-134 displayed a distribution pattern similar to GFP. This suggests that the c-terminal hydrophobic domain has an important role in determining the intracellular localization of TIG3. In addition, GFP-TIG31-164 retains the ability to inhibit cell function, while GFP-TIG31-134 is inactive.