Expression of Human PTEN-L in a Yeast Heterologous Model Unveils Specific N-Terminal Motifs Controlling PTEN-L Subcellular Localization and Function
Expression of Human PTEN-L in a Yeast Heterologous Model Unveils Specific N-Terminal Motifs Controlling PTEN-L Subcellular Localization and Function
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DOI：
10.3390/cells8121512
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发表时间：
2019-12-01
期刊：
影响因子：
6
通讯作者：
Cid, Victor J.
中科院分区：
文献类型：
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作者：
Fernandez-Acero, Teresa;Bertalmio, Eleonora;Cid, Victor J.
肿瘤抑制因子PTEN在几种类型的肿瘤和先天性疾病中经常下调、突变或丢失，包括PHTS（PTEN错构瘤肿瘤综合征）和ASD（自闭症谱系障碍）。PTEN是一种脂质磷酸酶，其对脂质信使PIP 3的活性抵消致癌磷脂酰肌醇3-激酶（PI 3 K）途径的刺激。最近，已经描述了在细胞中通过交替翻译起始产生的几种延伸形式的PTEN，其中，PTEN-L和PTEN-M代表最长的同种型。我们先前开发了人源化酵母模型，其中PI 3 K在酿酒酵母中的表达导致生长抑制，该生长抑制可以通过共表达PTEN来抑制。在这里，我们表明PTEN-L和PTEN-M在酵母中的表达导致对PI 3 K依赖性生长抑制的强烈抵消。N-末端标记的GFP-PTEN-L明显定位于酵母质膜。位于PTEN-L延伸或其缺失处的推定的膜结合螺旋的点突变将定位转移到核。此外，在突变体中，在PIP 2结合基序的碱性氨基酸簇和C2结构域的C α 2和CBR 3环处观察到从质膜到细胞核的转移。相反，C-末端标记的PTEN-L-GFP在酵母中显示线粒体定位，其通过去除前22个PTEN-L残基而转移到质膜。我们的研究结果表明，其空间和功能调节的N-末端延伸的替代PTEN亚型的重要作用。
The tumour suppressor PTEN is frequently downregulated, mutated or lost in several types of tumours and congenital disorders including PHTS (PTEN Hamartoma Tumour Syndrome) and ASD (Autism Spectrum Disorder). PTEN is a lipid phosphatase whose activity over the lipid messenger PIP3 counteracts the stimulation of the oncogenic phosphatidylinositol 3-kinase (PI3K) pathway. Recently, several extended versions of PTEN produced in the cell by alternative translation initiation have been described, among which, PTEN-L and PTEN-M represent the longest isoforms. We previously developed a humanized yeast model in which the expression of PI3K in Saccharomyces cerevisiae led to growth inhibition that could be suppressed by co-expression of PTEN. Here, we show that the expression of PTEN-L and PTEN-M in yeast results in robust counteracting of PI3K-dependent growth inhibition. N-terminally tagged GFP-PTEN-L was sharply localized at the yeast plasma membrane. Point mutations of a putative membrane-binding helix located at the PTEN-L extension or its deletion shifted localization to nuclear. Also, a shift from plasma membrane to nucleus was observed in mutants at basic amino acid clusters at the PIP2-binding motif, and at the C alpha 2 and CBR3 loops at the C2 domain. In contrast, C-terminally tagged PTEN-L-GFP displayed mitochondrial localization in yeast, which was shifted to plasma membrane by removing the first 22 PTEN-L residues. Our results suggest an important role of the N-terminal extension of alternative PTEN isoforms on their spatial and functional regulation.