Protein kinase B (AKT) is essential for cell survival, proliferation, and migration and has been associated with several diseases. Here, we demonstrate that inositol pol-yphosphate multikinase (IPMK's) lipid kinase property drives AKT activation via increasing membrane localization and activation of PDK1 (3-Phosphoinositide-dependent kinase 1), largely independent of class I PI3k (cPI3K). Deletion of IPMK impairs cell migration, which is partially associated with the abolition of PDK1-mediated ROCK1 disinhibition and subsequent myosin light chain (MLC) phosphorylation. IPMK is highly expressed in intestinal epithelial cells (IEC). Delet-ing IPMK in IEC reduced AKT phosphorylation and diminished the number of Paneth cells. Ablation of IPMK impaired IEC regeneration both basally and after chemotherapy-induced damage, suggesting a broad role for IPMK in activating AKT and intestinal tissue regeneration. In conclusion, the PI3k activity of IPMK is necessary for PDK1-mediated AKT activation and intestinal homeostasis.

Cocaine exerts its stimulant effect by inhibiting dopamine (DA) reuptake, leading to increased dopamine signaling. This action is thought to reflect the binding of cocaine to the dopamine transporter (DAT) to inhibit its function. However, cocaine is a relatively weak inhibitor of DAT, and many DAT inhibitors do not share cocaine’s behavioral actions. Further, recent reports show more potent actions of the drug, implying the existence of a high-affinity receptor for cocaine. We now report high-affinity binding of cocaine associated with the brain acid soluble protein 1 (BASP1) with a dissociation constant (Kd) of 7 nM. Knocking down BASP1 in the striatum inhibits [3H]cocaine binding to striatal synaptosomes. Depleting BASP1 in the nucleus accumbens but not the dorsal striatum diminishes locomotor stimulation in mice. Our findings imply that BASP1 is a pharmacologically relevant receptor for cocaine.

Trigeminal neuralgia, historically dubbed the “suicide disease,” is an exceedingly painful neurologic condition characterized by sudden episodes of intense facial pain. Unfortunately, the only U.S. Food and Drug Administration (FDA)–approved medication for trigeminal neuralgia carries substantial side effects, with many patients requiring surgery. Here, we identify the NRF2 transcriptional network as a potential therapeutic target. We report that cerebrospinal fluid from patients with trigeminal neuralgia accumulates reactive oxygen species, several of which directly activate the pain-transducing channel TRPA1. Similar to our patient cohort, a mouse model of trigeminal neuropathic pain also exhibits notable oxidative stress. We discover that stimulating the NRF2 antioxidant transcriptional network is as analgesic as inhibiting TRPA1, in part by reversing the underlying oxidative stress. Using a transcriptome-guided drug discovery strategy, we identify two NRF2 network modulators as potential treatments. One of these candidates, exemestane, is already FDA-approved and may thus be a promising alternative treatment for trigeminal neuropathic pain.

Synapses connect discrete neurons into vast networks that send, receive, and encode diverse forms of information. Synaptic function and plasticity, the neuronal process of adapting to diverse and variable inputs, depend on the dynamic nature of synaptic molecular components, which is mediated in part by cell adhesion signaling pathways. Here, we found that the enzyme biliverdin reductase (BVR) physically links together key focal adhesion signaling molecules at the synapse. BVR -null ( BVR −/− ) mice exhibited substantial deficits in learning and memory on neurocognitive tests, and hippocampal slices in which BVR was postsynaptically depleted showed deficits in electrophysiological responses to stimuli. RNA sequencing, biochemistry, and pathway analyses suggested that these deficits were mediated through the loss of focal adhesion signaling at both the transcriptional and biochemical level in the hippocampus. Independently of its catalytic function, BVR acted as a bridge between the primary focal adhesion signaling kinases FAK and Pyk2 and the effector kinase Src. Without BVR, FAK and Pyk2 did not bind to and stimulate Src, which then did not phosphorylate the N -methyl- d -aspartate (NMDA) receptor, a critical posttranslational modification for synaptic plasticity. Src itself is a molecular hub on which many signaling pathways converge to stimulate NMDAR-mediated neurotransmission, thus positioning BVR at a prominent intersection of synaptic signaling.

Cocaine exerts its stimulant effect by inhibiting dopamine reuptake leading to increased dopamine signaling. This action is thought to reflect binding of cocaine to the dopamine transporter (DAT) to inhibit its function. However, cocaine is a relatively weak inhibitor of DAT, and many DAT inhibitors do not share the behavioral actions of cocaine. We previously showed that toxic levels of cocaine induce autophagic neuronal cell death. Here, we show that subnanomolar concentrations of cocaine elicit neural autophagy in vitro and in vivo. Autophagy inhibitors reduce the locomotor stimulant effect of cocaine in mice. Cocaine-induced autophagy degrades transporters for dopamine but not serotonin in the nucleus accumbens. Autophagy inhibition impairs cocaine conditioned place preference in mice. Our findings indicate that autophagic degradation of DAT modulates behavioral actions of cocaine.

Sleep is a highly conserved state, suggesting that sleep's benefits outweigh the increased vulnerability it brings. Yet, little is known about how sleep fulfills its functions. Here, we used video tracking in tethered flies to identify a discrete deep sleep stage in Drosophila, termed proboscis extension sleep, that is defined by repeated stereotyped proboscis extensions and retractions. Proboscis extension sleep is accompanied by highly elevated arousal thresholds and decreased brain activity, indicative of a deep sleep state. Preventing proboscis extensions increases injury-related mortality and reduces waste clearance. Sleep deprivation reduces waste clearance and during subsequent rebound sleep, sleep, proboscis extensions, and waste clearance are increased. Together, these results provide evidence of a discrete deep sleep stage that is linked to a specific function and suggest that waste clearance is a core and ancient function of deep sleep.

Significance d -amino acids are increasingly recognized as important signaling molecules in the mammalian central nervous system. Cysteine is the amino acid with the fastest in vitro spontaneous racemization rate, but its d -stereoisomer has not been examined. Here, we establish the presence of endogenous d -cysteine in the mammalian brain. Using sensitive and specific assays, we delineate its actions as a negative regulator of growth factor signaling during cortical development and identify a putative binding partner mediating these effects. By describing the newest member of the d -amino acid family, we open an avenue of research into the functions of these multifaceted signaling molecules.

Cocaine exerts its stimulant effect by inhibiting dopamine reuptake leading to increased dopamine signaling. This action is thought to reflect binding of cocaine to the dopamine transporter (DAT) to inhibit its function. However, cocaine is a relatively weak inhibitor of DAT, and many DAT inhibitors do not share the behavioral actions of cocaine. Here we show that sub‐nanomolar concentrations of cocaine elicit neural autophagy in vitro and in vivo. Pharmacologic inhibition of autophagy significantly reduces the locomotor stimulant effect of cocaine in mice. Autophagy depletes transporters for dopamine but not serotonin in the nucleus accumbens following cocaine injection. The dopamine transporter is enriched in the ventral midbrain lysosomal fraction following intraperitoneal injection of cocaine, which is reversed by inhibition of autophagy. Furthermore, autophagy inhibitors significantly reduce dopamine levels in the nucleus accumbens following cocaine injection. Taken together, these findings suggest that the behavioral stimulant effect of cocaine is mediated at least in part by autophagic degradation of DAT.Support or Funding InformationFunding: this work was supported by U.S. Public Health Service Grants DA00266 and DA044123 to SHS and a NARSAD Young Investigator Grant (grant # 25360) from the Brain & Behavior Foundation to MMH. Support for this research was provided in part by the National Institute on Drug Abuse ‐ Intramural Research Program, NIH/DHHS (Z1A DA000611).

Cocaine is a behavioral stimulant with substantial abuse potential related to its positively rewarding actions. Definitive molecular mechanisms of action have not been established, though cocaine is known to inhibit the reuptake inactivation of monoamine neurotransmission at high nanomolar to low micromolar concentrations. There is evidence for significantly more potent neurochemical and behavioral actions of cocaine that could not be attributed to the inhibition of monoamine transporters. Thus, evidence for a specific, high affinity cocaine receptor that mediates its behavioral actions has been lacking. In the present study we report high affinity binding of cocaine to the membrane‐associated protein BASP1, which appears to be a pharmacologically relevant cocaine receptor. Utilizing affinity pull‐down, mass spectrometry and ligand binding assays, we establish that BASP1 is a high‐affinity cocaine binding protein (Kd 7 nM). Our data show that knocking down BASP1 in the nucleus accumbens or striatum (pre‐ and post‐synaptic) inhibits behavioral actions of cocaine and reduces [3H]cocaine binding to striatal synaptosomes respectively. Taken together, our data suggest that BASP1 is a high‐affinity receptor for cocaine.Support or Funding Information Fundingthis work was supported by U.S. Public Health Service Grants DA00266 and DA044123 to SHS and a NARSAD Young Investigator Grant (grant # 25360) from the Brain & Behavior Foundation to MMH.

Sodium/potassium-transporting adenosine triphosphatase (Na+/K+-ATPase) is one of the most abundant cell membrane proteins and is essential for eukaryotes. Endogenous negative regulators have long been postulated to play an important role in regulating the activity and stability of Na+/K+-ATPase, but characterization of these regulators has been elusive. Mechanisms of regulating Na+/K+-ATPase homeostatic turnover are unknown. Here, we report that 5-diphosphoinositol 1,2,3,4,6-pentakisphosphate (5-InsP7), generated by inositol hexakisphosphate kinase 1 (IP6K1), promotes physiological endocytosis and downstream degradation of Na+/K+-ATPase-α1. Deletion of IP6K1 elicits a twofold enrichment of Na+/K+-ATPase-α1 in plasma membranes of multiple tissues and cell types. Using a suite of synthetic chemical biology tools, we found that 5-InsP7 binds the RhoGAP domain of phosphatidylinositol 3-kinase (PI3K) p85α to disinhibit its interaction with Na+/K+-ATPase-α1. This recruits adaptor protein 2 (AP2) and triggers the clathrin-mediated endocytosis of Na+/K+-ATPase-α1. Our study identifies 5-InsP7 as an endogenous negative regulator of Na+/K+-ATPase-α1.