Dagunts Aleksandra, Adoff Hayden, Novy Brandon, Maria Monica De, Lobingier Braden T
Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR 97239, USA.
bioRxiv. 2024 Dec 2:2024.12.02.626482. doi: 10.1101/2024.12.02.626482.
The mu opioid receptor (MOR) is protected from opioid-induced trafficking to lysosomes and proteolytic downregulation by its ability to access the endosomal recycling pathway through its C-terminal recycling motif, LENL. MOR sorting towards the lysosome results in downregulation of opioid signaling while recycling of MOR to the plasma membrane preserves signaling function. However, the mechanisms by which LENL promotes MOR recycling are unknown, and this sequence does not match any known consensus recycling motif. Here we took a functional genomics approach with a comparative genome-wide screen design to identify genes which control opioid receptor expression and downregulation. We identified 146 hits including all three subunits of the endosomal Retromer complex. We show that the LENL motif in MOR is a novel Retromer recycling motif and that LENL is a necessary, sufficient, and conserved mechanism to give MOR access to the Retromer recycling pathway and protect MOR from agonist-induced downregulation to multiple clinically relevant opioids including fentanyl and methadone.
μ阿片受体（MOR）通过其C末端循环基序LENL进入内体循环途径的能力，免受阿片类药物诱导的向溶酶体的转运和蛋白水解下调。MOR向溶酶体的分选导致阿片类信号传导的下调，而MOR再循环回质膜则保留信号传导功能。然而，LENL促进MOR再循环的机制尚不清楚，并且该序列与任何已知的共有再循环基序均不匹配。在这里，我们采用功能基因组学方法，通过比较全基因组筛选设计来鉴定控制阿片受体表达和下调的基因。我们鉴定出146个命中基因，包括内体Retromer复合物的所有三个亚基。我们表明，MOR中的LENL基序是一种新型的Retromer再循环基序，并且LENL是使MOR进入Retromer再循环途径并保护MOR免受激动剂诱导的下调至多种临床相关阿片类药物（包括芬太尼和美沙酮）的必要、充分且保守的机制。
