Distinct in vitro interaction pattern of dopamine receptor subtypes with adaptor proteins involved in post‐endocytotic receptor targeting

Abstract

The mechanisms underlying targeted sorting of endocytosed receptors for recycling to the plasma membrane or degradation in lysosomes are poorly understood. In this report, the C-terminal tails of the ¢ve dopamine receptors (D1^D5) were expressed as glutathione S-transferase (GST) fusion proteins and studied for their interaction with ezrin^radixin^moesin-binding phosphoprotein 50 (EBP50) and N-ethylmaleimide-sensitive factor (NSF), which are known to be involved in postendocytic recycling of receptors back to the plasma membrane, and with sorting nexin 1 (SNX1), known to be involved in targeting receptors to lysosomal degradation. EBP50 did not bind any of the dopamine receptor tails. NSF bound strongly to D1 and D5 and only weakly to D2, D3 and D4. However, SNX1 clearly distinguished between D1 and D5, as only D5 bound strongly to this protein. This report shows that there are distinct interaction patterns for NSF and SNX1 to the various dopamine receptor subtypes. ß

神经细胞中多巴胺d1和d5受体不同亚细胞分布和胞内转运的特性

“…D1R interacts with NMDA receptor subunits NR1 and NR2A and inhibits the NMDA-mediated current through its C-terminal tails [24] ; While D5R interacts with GABAa receptor 2 (short) subunit and enables mutually functional inhibition through it's C-terminus [25] . In a systematic binding study of the C-termini of all dopamine receptor subtypes, D5R but not D1R C-terminus selectively and strongly bound to a membrane-associated protein sorting nexin 1 (SNX1) [26] . In addition, the C-termini of D1-like receptors also governed their distinct binding affinity to agonists [27,28] .…”

Presynaptic D1Dopamine Receptors in Primate Prefrontal Cortex: Target-Specific Expression in the Glutamatergic Synapse

“…Although axoplasmic labeling of D 1 Rs could potentially represent a diffusion artifact (i.e., of axolemmal D 1 Rs), it should be carefully interpreted given that cytoplasmic occurrence was reported for postsynaptic DARs and other receptor systems as a phase of dynamic trafficking from and toward the plasmalemma (Bloch et al, 1999;Malinow and Malenka, 2002;Heydorn et al, 2004). Whether presynaptic (and postsynaptic) D 1 Rs undergo similar dynamic internalization in the PFC is currently unknown.…”

Microdomains for Dopamine Volume Neurotransmission in Primate Prefrontal Cortex

“…Compared with the D 1 R, which undergoes dynamin-dependent endocytosis involving clathrincoated pits (Bloch et al, 1999;Vickery and Zastrow, 1999), little is known about the D 5 R regarding its handling after agonist stimulation. Although it appears to undergo agonist-induced internalization, similar to the D 1 R, recent evidence suggests that after endocytosis the D 5 R is shorted for degradation in the lysosomes (Heydorn et al, 2004).…”