Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.
Department of Chemistry, Faculty of Science, Yamagata University, Shirakawa, Yamagata 990-8560, Japan.
J Cell Sci. 2023 Mar 15;136(6). doi: 10.1242/jcs.260566. Epub 2023 Mar 2.
Proper control of epidermal growth factor receptor (EGFR) signaling is important for maintaining cellular homeostasis. Given that EGFR signaling occurs at the plasma membrane and endosomes following internalization, endosomal trafficking of EGFR spatiotemporally regulates EGFR signaling. In this process, leucine-rich repeat kinase 1 (LRRK1) has multiple roles in kinase activity-dependent transport of EGFR-containing endosomes and kinase-independent sorting of EGFR into the intraluminal vesicles (ILVs) of multivesicular bodies. Active, phosphorylated EGFR inactivates the LRRK1 kinase activity by phosphorylating Y944. In this study, we demonstrate that LRRK1 facilitates EGFR dephosphorylation by PTP1B (also known as PTPN1), an endoplasmic reticulum (ER)-localized protein tyrosine phosphatase, at the ER-endosome contact site, after which EGFR is sorted into the ILVs of endosomes. LRRK1 is required for the PTP1B-EGFR interaction in response to EGF stimulation, resulting in the downregulation of EGFR signaling. Furthermore, PTP1B activates LRRK1 by dephosphorylating pY944 on the contact site, which promotes the transport of EGFR-containing endosomes to the perinuclear region. These findings provide evidence that the ER-endosome contact site functions as a hub for LRRK1-dependent signaling that regulates EGFR trafficking.
表皮生长因子受体 (EGFR) 信号的适当控制对于维持细胞内稳态很重要。鉴于 EGFR 信号在内化后发生在质膜和内体中，因此 EGFR 的内体运输在空间和时间上调节 EGFR 信号。在这个过程中，富含亮氨酸重复激酶 1 (LRRK1) 在 EGFR 含有内体的激酶活性依赖性运输和激酶独立的 EGFR 分选到多泡体的腔内小泡 (ILVs) 中具有多种作用。活性磷酸化的 EGFR 通过磷酸化 Y944 使 LRRK1 激酶失活。在这项研究中，我们证明 LRRK1 在 EGFR 被分选到内体的 ILVs 之前，在 ER-内体接触部位通过内质网 (ER) 定位的蛋白酪氨酸磷酸酶 PTP1B（也称为 PTPN1）促进 EGFR 的去磷酸化，随后 EGFR 被分选到内体的 ILVs 中。在 EGF 刺激下，LRRK1 是 PTP1B-EGFR 相互作用所必需的，导致 EGFR 信号下调。此外，PTP1B 通过去磷酸化接触部位的 pY944 激活 LRRK1，从而促进含有 EGFR 的内体向核周区域的运输。这些发现提供了证据，表明 ER-内体接触部位作为 LRRK1 依赖性信号的枢纽，调节 EGFR 运输。
