Protein interacting with Amyloid Precursor Protein (APP) tail 1 (PAT1) also called APPBP2 or Ara 67 has different targets such as APP or androgen receptor and is expressed in several tissues. PAT1 is known to be involved in the subcellular trafficking of its targets. We previously observed in primary neurons that PAT1 is poorly associated with APP at the cell surface. Here we show that PAT1 colocalizes with vesicles close to the cell surface labeled with Rab5, Rab4, EEA1 and Rabaptin-5 but not with Rab11 and Rab7. Moreover, PAT1 expression regulates the number of EEA1 and Rab5 vesicles, and endocytosis/recycling of the transferrin receptor. In addition, low levels of PAT1 decrease the size of transferrin-colocalized EEA1 vesicles with time following transferrin uptake. Finally, overexpression of the APP binding domain to PAT1 is sufficient to compromise endocytosis. Altogether, these data suggest that PAT1 is a new actor in transferrin early endocytosis. Whether this new function of PAT1 may have consequences in pathology remains to be determined.

中文翻译：

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与淀粉样蛋白前体蛋白 tail-1 (PAT1) 相互作用的蛋白质参与早期内吞作用。


与淀粉样前体蛋白 (APP) 尾部 1 (PAT1) 相互作用的蛋白质也称为 APPBP2 或 Ara 67，具有不同的靶标，例如 APP 或雄激素受体，并在多种组织中表达。已知 PAT1 参与其靶标的亚细胞运输。我们之前在初级神经元中观察到 PAT1 与细胞表面的 APP 相关性较差。在这里，我们发现 PAT1 与靠近细胞表面的囊泡共定位，这些囊泡被 Rab5、Rab4、EEA1 和 Rabaptin-5 标记，但不与 Rab11 和 Rab7 标记。此外，PAT1 表达调节 EEA1 和 Rab5 囊泡的数量以及转铁蛋白受体的内吞作用/再循环。此外，低水平的 PAT1 会随着转铁蛋白摄取后时间的推移，降低转铁蛋白共定位的 EEA1 囊泡的大小。最后，APP 结合域对 PAT1 的过度表达足以损害内吞作用。总之，这些数据表明 PAT1 是转铁蛋白早期内吞作用的新作用者。 PAT1 的这种新功能是否会对病理学产生影响仍有待确定。