Substrate and inhibitor binding of human GABA transporter 3.

GABA (g-aminobutyric acid) transporter 3 (GAT3) is primarily found in glial cells and is essential for regulating GABA homeostasis in the central nervous system by mediating GABA uptake. Consequently, GAT3 has emerged as a significant therapeutic target for the treatment of epilepsy. In this study, we present the cryoelectron microscopy (cryo-EM) structures of GAT3 bound to its substrate GABA, the selective inhibitor SNAP-5114, and in the substrate-free state.

Molecular mechanism of drug inhibition of URAT1.

Hyperuricemia, characterized by elevated serum urate levels, is a key factor in the pathogenesis of gout. URAT1 is essential for renal urate reabsorption and has emerged as a critical therapeutic target for managing hyperuricemia. However, the precise transport mechanism and the inhibitory effects of uricosuric drugs on URAT1 remain unclear.

The induced-fit and catalytic mechanisms of human G6PC1.

Human glucose-6-phosphatase catalytic subunit 1 (hG6PC1) is a key enzyme in glucose metabolism, governing the final common step of gluconeogenesis and glycogenolysis, and directly regulating energy homeostasis. Aberrant mutations in G6PC1 directly cause glycogen storage disease type 1a, which is characterized by chronic hypoglycemia and glycogen accumulation. Additionally, abnormal G6PC1 function leads to increased fasting blood glucose.

Modulation of the human GlyT1 by clinical drugs and cholesterol.

Glycine transporter 1 (GlyT1) is a key player in shaping extracellular glutamatergic signaling processes and holds promise for treating cognitive impairments associated with schizophrenia by inhibiting its activity and thus enhancing the function of NMDA receptors. Despite its significant role in physiological and pharmacology, its modulation mechanism by clinical drugs and internal lipids remains elusive. Here, we determine cryo-EM structures of GlyT1 in its apo state and in complex with clinical trial drugs iclepertin and sarcosine.

Structural basis of urea transport by Arabidopsis thaliana DUR3.

Urea is a primary nitrogen source used as fertilizer in agricultural plant production and a crucial nitrogen metabolite in plants, playing an essential role in modern agriculture. In plants, DUR3 is a proton-driven high-affinity urea transporter located on the plasma membrane. It not only absorbs external low-concentration urea as a nutrient but also facilitates nitrogen transfer by recovering urea from senescent leaves.

Binding mechanism and antagonism of the vesicular acetylcholine transporter VAChT.

The vesicular acetylcholine transporter (VAChT) has a pivotal role in packaging and transporting acetylcholine for exocytotic release, serving as a vital component of cholinergic neurotransmission. Dysregulation of its function can result in neurological disorders. It also serves as a target for developing radiotracers to quantify cholinergic neuron deficits in neurodegenerative conditions.

Ion coupling and inhibitory mechanisms of the human presynaptic high-affinity choline transporter CHT1.

In cholinergic neurons, choline is the precursor of the excitatory neurotransmitter acetylcholine (ACh), which plays a fundamental role in the brain. The high-affinity choline transporter, CHT1, mediates the efficient recycling of choline to facilitate ACh synthesis in the presynapse. Here, we report high-resolution cryoelectron microscopic (cryo-EM) structures of CHT1 in complex with the inhibitors HC-3 and ML352, the substrate choline, and a substrate-free state.

Dopamine reuptake and inhibitory mechanisms in human dopamine transporter.

The dopamine transporter has a crucial role in regulation of dopaminergic neurotransmission by uptake of dopamine into neurons and contributes to the abuse potential of psychomotor stimulants. Despite decades of study, the structure, substrate binding, conformational transitions and drug-binding poses of human dopamine transporter remain unknown. Here we report structures of the human dopamine transporter in its apo state, and in complex with the substrate dopamine, the attention deficit hyperactivity disorder drug methylphenidate, and the dopamine-uptake inhibitors GBR12909 and benztropine.

Transport and inhibition mechanisms of the human noradrenaline transporter.

The noradrenaline transporter (also known as norepinephrine transporter) (NET) has a critical role in terminating noradrenergic transmission by utilizing sodium and chloride gradients to drive the reuptake of noradrenaline (also known as norepinephrine) into presynaptic neurons. It is a pharmacological target for various antidepressants and analgesic drugs. Despite decades of research, its structure and the molecular mechanisms underpinning noradrenaline transport, coupling to ion gradients and non-competitive inhibition remain unknown.

Structural insights into the allosteric effects of the antiepileptic drug topiramate on the Ca2.3 channel.

The R-type voltage-gated calcium channel Ca2.3 is predominantly located in the presynapse and is implicated in distinct types of epileptic seizures. It has consequently emerged as a molecular target in seizure treatment.

Transport mechanism of presynaptic high-affinity choline uptake by CHT1.

Choline is a vital nutrient and a precursor for the biosynthesis of essential metabolites, including acetylcholine (ACh), that play a central role in fetal development, especially in the brain. In cholinergic neurons, the high-affinity choline transporter (CHT1) provides an extraordinarily efficient reuptake mechanism to reutilize choline derived from intrasynaptical ACh hydrolysis and maintain ACh synthesis in the presynapse. Here, we determined structures of human CHT1 in three discrete states: the outward-facing state bound with the competitive inhibitor hemicholinium-3 (HC-3); the inward-facing occluded state bound with the substrate choline; and the inward-facing apo open state.

Structural bases of inhibitory mechanism of Ca1.2 channel inhibitors.

The voltage-gated calcium channel Ca1.2 is essential for cardiac and vessel smooth muscle contractility and brain function. Accumulating evidence demonstrates that malfunctions of Ca1.

Transport mechanism and pharmacology of the human GlyT1.

The glycine transporter 1 (GlyT1) plays a crucial role in the regulation of both inhibitory and excitatory neurotransmission by removing glycine from the synaptic cleft. Given its close association with glutamate/glycine co-activated NMDA receptors (NMDARs), GlyT1 has emerged as a central target for the treatment of schizophrenia, which is often linked to hypofunctional NMDARs. Here, we report the cryo-EM structures of GlyT1 bound with substrate glycine and drugs ALX-5407, SSR504734, and PF-03463275.

TRPV1 analgesics disturb core body temperature via a biased allosteric mechanism involving conformations distinct from that for nociception.

Efforts on developing transient receptor potential vanilloid 1 (TRPV1) drugs for pain management have been hampered by deleterious hypo- or hyperthermia caused by TRPV1 agonists/antagonists. Here, we compared the effects of four antagonists on TRPV1 polymodal gating and core body temperature (CBT) in Trpv1, Trpv1, and Trpv1. Neither the effect on proton gating nor drug administration route, hair coverage, CBT rhythmic fluctuations, or inflammation had any influence on the differential actions of TRPV1 drugs on CBT.