Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands.
Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas, Pablo de Olavide University, Seville, Spain.
J Cell Biol. 2020 Oct 5;219(10). doi: 10.1083/jcb.201906023.
Retention of peroxisomes in yeast mother cells requires Inp1, which is recruited to the organelle by the peroxisomal membrane protein Pex3. Here we show that Hansenula polymorpha Inp1 associates peroxisomes to the plasma membrane. Peroxisome-plasma membrane contact sites disappear upon deletion of INP1 but increase upon INP1 overexpression. Analysis of truncated Inp1 variants showed that the C terminus is important for association to the peroxisome, while a stretch of conserved positive charges and a central pleckstrin homology-like domain are important for plasma membrane binding. In cells of a PEX3 deletion, strain Inp1-GFP localizes to the plasma membrane, concentrated in patches near the bud neck and in the cortex of nascent buds. Upon disruption of the actin cytoskeleton by treatment of the cells with latrunculin A, Inp1-GFP became cytosolic, indicating that Inp1 localization is dependent on the presence of an intact actin cytoskeleton.
酵母母细胞中过氧化物酶体的保留需要 Inp1，它通过过氧化物酶体膜蛋白 Pex3 被招募到细胞器。在这里，我们表明，汉逊酵母的 Inp1 将过氧化物酶体与质膜联系起来。过氧化物酶体-质膜接触点在 INP1 缺失时消失，但在 INP1 过表达时增加。对截断的 Inp1 变体的分析表明，C 端对于与过氧化物酶体的结合很重要，而一段保守的正电荷和中央 Pleckstrin 同源结构域对于质膜结合很重要。在 PEX3 缺失的细胞中，Inp1-GFP 定位于质膜，在芽颈附近的斑块和新形成的芽的皮质中浓缩。在用拉曲菌素 A 处理细胞破坏肌动蛋白细胞骨架后，Inp1-GFP 成为细胞质，表明 Inp1 的定位依赖于完整的肌动蛋白细胞骨架的存在。
