A subset of peroxisomes is retained at the mother cell cortex by the Pex3–Inp1 complex. We identify Inp1 as the first known plasma membrane–peroxisome (PM-PER) tether by demonstrating that Inp1 meets the predefined criteria that a contact site tether protein must adhere to. We show that Inp1 is present in the correct subcellular location to interact with both the plasma membrane and peroxisomal membrane and has the structural and functional capacity to be a PM-PER tether. Additionally, expression of artificial PM-PER tethers is sufficient to restore retention in inp1Δ cells. We show that Inp1 mediates peroxisome retention via an N-terminal domain that binds PI(4,5)P2 and a C-terminal Pex3-binding domain, forming a bridge between the peroxisomal membrane and the plasma membrane. We provide the first molecular characterization of the PM-PER tether and show it anchors peroxisomes at the mother cell cortex, suggesting a new model for peroxisome retention.

中文翻译：

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Pex3-Inp1 复合物将酵母过氧化物酶体束缚在质膜上

过氧化物酶体的一个子集被 Pex3-Inp1 复合物保留在母细胞皮层。通过证明 Inp1 符合接触位点系链蛋白必须遵守的预定义标准，我们将 Inp1 确定为第一个已知的质膜过氧化物酶体 (PM-PER) 系链。我们证明 Inp1 存在于正确的亚细胞位置，与质膜和过氧化物酶体膜相互作用，并且具有作为 PM-PER 系链的结构和功能能力。此外，人工 PM-PER 系链的表达足以恢复 inp1Δ 细胞中的保留。我们发现 Inp1 通过结合 PI(4,5)P2 的 N 端结构域和 C 端 Pex3 结合结构域介导过氧化物酶体保留，从而在过氧化物酶体膜和质膜之间形成桥梁。我们提供了 PM-PER 系链的第一个分子表征，并表明它将过氧化物酶体锚定在母细胞皮层，这提出了过氧化物酶体保留的新模型。