Bidirectional transfer of homeoprotein EN2 across the plasma membrane requires PIP2
Bidirectional transfer of homeoprotein EN2 across the plasma membrane requires PIP2
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DOI：
10.1242/jcs.244327
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发表时间：
2020-07-01
影响因子：
4
通讯作者：
Joliot, Alain
中科院分区：
文献类型：
--
作者：
Amblard, Irene;Dupont, Edmond;Joliot, Alain
同源蛋白是一类转录因子，具有细胞间运输的意想不到的特性，赋予同源蛋白一种旁分泌的作用模式。同型蛋白旁分泌作用参与模式过程的控制，包括轴突引导、大脑可塑性和边界形成。内化和分泌是细胞间转移的两个步骤，依赖于非常规的机制，但所涉及的细胞机制仍需充分表征。由于设计了新的定量和敏感的方法来研究培养的HeLa细胞内的同型蛋白转移，我们证明了磷脂酰肌醇(4,5)-二磷酸（PIP2）和胆固醇在同型盒蛋白EN2 （EN2）在质膜上的易位中的核心作用。通过药物和酶治疗，我们发现PIP2的分泌和内化都受到PIP2水平的调节。在EN2运输过程中，PIP2和胆固醇的需求与它们在人工双分子层中对这种蛋白的选择性亲和力相关，这种亲和力在EN2旁分泌缺陷突变体中急剧降低。我们认为，在同型蛋白分泌和内化过程中发生的双向质膜易位事件是一个共同过程的一部分。
Homeoproteins are a class of transcription factors sharing the unexpected property of intercellular trafficking that confers to homeoproteins a paracrine mode of action. Homeoprotein paracrine action participates in the control of patterning processes, including axonal guidance, brain plasticity and boundary formation. Internalization and secretion, the two steps of intercellular transfer, rely on unconventional mechanisms, but the cellular mechanisms at stake still need to be fully characterized. Thanks to the design of new quantitative and sensitive assays dedicated to the study of homeoprotein transfer within HeLa cells in culture, we demonstrate a core role of phosphatidylinositol (4,5)-bisphosphate (PIP2) together with cholesterol in the translocation of the homeobox protein engrailed-2 (EN2) across the plasma membrane. By using drug and enzyme treatments, we show that both secretion and internalization are regulated according to PIP2 levels. The requirement for PIP2 and cholesterol in EN2 trafficking correlates with their selective affinity for this protein in artificial bilayers, which is drastically decreased in a paracrine-deficient mutant of EN2. We propose that the bidirectional plasma membrane translocation events that occur during homeoprotein secretion and internalization are parts of a common process.