Parkin-mediated K63-polyubiquitination targets ubiquitin C-terminal hydrolase L1 for degradation by the autophagy-lysosome system

Ubiquitin C-terminal hydrolase L1 (UCH-L1) is a key neuronal deubiquitinating enzyme which is mutated in Parkinson disease (PD) and in childhood-onset neurodegenerative disorder with optic atrophy. Furthermore, reduced UCH-L1 protein levels are associated with a number of neurodegenerative diseases, whereas up-regulation of UCH-L1 protein expression is found in multiple types of cancer. However, very little is known about how UCH-L1 protein level is regulated in cells. Here, we report that UCH-L1 is a novel interactor and substrate of PD-linked E3 ubiquitin-protein ligase parkin. We find that parkin mediates K63-linked polyubiquitination of UCH-L1 in cooperation with the Ubc13/Uev1a E2 ubiquitin-conjugating enzyme complex and promotes UCH-L1 degradation by the autophagy-lysosome pathway. Targeted disruption of parkin gene expression in mice causes a significant decrease in UCH-L1 ubiquitination with a concomitant increase in UCH-L1 protein level in brain, supporting an in vivo role of parkin in regulating UCH-L1 ubiquitination and degradation. Our findings reveal a direct link between parkin-mediated ubiquitin signaling and UCH-L1 regulation, and they have important implications for understanding the roles of these two proteins in health and disease.     

Prolongation of hypnosis by 5-hydroxytryptamine (Serotonin)

Zusammenfassung Die Angabe, dass 5-Oxytryptamin (Serotonin) die Chloralhydrat- oder Barbitursäure-Hypnose bei Mäusen verlängern kann, wurde bestätigt. Da aber Stoffe wie Adrenalin und Histamin den gleichen Effekt zeigten, erscheint es möglich, dass die hypnoseverlängernde Eigenschaft des 5-Oxytryptamin auf einen relativ unspezifischen, vaskulären Effekt zurückzuführen ist.     

Trace element stimulation of keratin (Hair) degradation by oral keratinolytic microflora

Zusammenfassung Nach der Proteolyse-Chelationstheorie der Zahnkaries werden organische und anorganische Bestandteile des Zahnschmelzes mehr oder weniger gleichzeitig abgebaut. Die Ergebnisse dieser Untersuchungen zeigen, dass 1. mineralische Bestandteile des Schmelzes die mikrobiologische Zersetzung des Keratins fördern und dass 2. die enzymatische Zersetzung des Keratins Stoffe entwickelt, welche die Apatitauflösung mittels Chelation fördern.

---

---

This investigation was supported in part by a research grant D-182(C) from the National Institute of Dental Research of the National Institutes of Health, United States Public Health Service.     

Metabolism of a pharmacologically active pyrrolidine derivative (prolintane) by lactam formation

Zusammenfassung Prolintan, N-1-(-Benzylbutyl)-Pyrrolidin, wurde in Kaninchen durch ein Mikrosomensystem der Leber in das entsprechende Laktam, N-1-(-Benzylbutyl)-Pyrrolidin-2-on, umgebaut. Das gleiche Stoffwechselprodukt fand sich auch im Gewebe von Ratten, denen das Medikament gegeben wurde; allenfalls Spuren davon wurden im Urin der Ratten ausgeschieden.

---

---

We thank Dr.D. C. Remy for a sample of syntheticdl-1-(-propylphenethyl)-pyrrolidin-2-one.     

1-(Substituted)benzyl-5-aminoimidazole-4-carboxamides are potent orally active inhibitors ofTrypanosoma cruzi in mice

Summary 1-(Substituted)benzyl-5-aminoimidazole-4-carboxamides are potent orally active inhibitors ofTrypanosoma cruzi infections in mice. The most active compounds are the 1-(4-chlorobenzyl)- and 1-(3,4-dichlorobenzyl)-analogs (L-153,094 [2] and L-153,153 [4], resp.) which are approximately 7-fold more potent upon oral administration than nifurtimox (Lampit) in suppressing parasite levels in the blood of mice with acuteTrypanosoma cruzi infections.     

Some factors affect the degradation of (2-chloroethyl) trimethylammonium chloride by wheat plant extracts

Zusammenfassung Extrakte aus Weizenpflanzen enthalten ein System, welches Chlorocholinchlorid zu Cholinchlorid umwandelt. Dieses System wird durch pH, aber nicht durch die Temperatur beeinflusst und hat zwei Komponenten; die erste wird durch ZnCl₂ gefällt, und die andere ist dialysierbar.     

1-(substituted)benzyl-5-aminoimidazole-4-carboxamides are potent orally active inhibitors of Trypanosoma cruzi in mice

1-(Substituted)benzyl-5-aminoimidazole-4-carboxamides are potent orally active inhibitors of Trypanosoma cruzi infections in mice. The most active compounds are the 1-(4-chlorobenzyl)- and 1-(3,4-dichlorobenzyl)-analogs (L-153,094 [2] and L-153,153 [4], resp.) which are approximately 7-fold more potent upon oral administration than nifurtimox (Lampit) in suppressing parasite levels in the blood of mice with acute Trypanosoma cruzi infections.     

A pivotal role for serotonin (5HT) in the regulation of beta adrenoceptors by antidepressants: reversibility of the action of parachlorophenylalanine by 5-hydroxytroptophan

Summary An acute reduction in the synaptic availability of serotonin (5HT) by p-chlorophenlalanine (PCPA) nullifies the decrease in the density of cortical beta adrenoceptors caused by desipramine (DMI) but does not appreciably alter the attenuation of the norepinephrine (NE) sensitive adenylate cyclase. The analysis of competition-binding curves of [³H]-dihydroalprenolol shows that the affinity of the agonist (–)-isoproterenol for cortical beta adrenoceptors is profoundly reduced following PCPA. This reduction in agonist affinity is enhanced by DMI. Resupplying 5HT by by-passing trptophan hydroxylase inhibition, by administering 5-hydroxytryptophan, converts a DMI non-responsive to a DMI responsive beta adrenoceptor population and shifts the markedly decreased agonist affinity towards the affinity values found in control preparations. The results demonstrate the pivotal role of 5HT in the regulation of the density and agonist affinity characteristics of cortical beta adrenoceptors and contribute to the scientific basis of the serotonin-norepinephrine link hypothesis of affective disorders.Acknowledgments. This work was supported by USPHS grant MH-29228 and the Tennessee Department of Mental Health and Mental Retardation. Present address of L. R. Sterank: NOVA Pharmaceutical Corporation, Baltimore (MD 21228, USA).     

SNX3-dependent regulation of epidermal growth factor receptor (EGFR) trafficking and degradation by aspirin in epidermoid carcinoma (A-431) cells

Since being introduced globally as aspirin in 1899, acetylsalicylic acid has been widely used as an analgesic, anti-inflammation, anti-pyretic, and anti-thrombotic drug for years. Aspirin had been reported to down-regulate surface expression of CD40, CD80, CD86, and MHCII in myeloid dendritic cells (DC), which played essential roles in regulating the immune system. We hypothesized that the down-regulation of these surface membrane proteins is partly due to the ability of aspirin in regulating trafficking/sorting of endocytosed surface membrane proteins. By using an established epidermoid carcinoma cell line (A-431), which overexpresses the epidermal growth factor receptor (EGFR) and transferrin receptor (TfnR), we show that aspirin (1) reduces cell surface expression of EGFR and (2) accumulates endocytosed-EGFR and -TfnR in the early/sorting endosome (ESE). Further elucidation of the mechanism suggests that aspirin enhances recruitment of SNX3 and SNX5 to membranes and consistently, both SNX3 and SNX5 play essential roles in the aspirin-mediated accumulation of endocytosed-TfnR at the ESE. This study sheds light on how aspirin may down-regulate surface expression of EGFR by inhibiting/delaying the exit of endocytosed-EGFR from the ESE and recycling of endocytosed-EGFR back to the cell surface.     

Observations on the 5-hydroxytryptamine (Enteramine) release caused by reserpine in the rat

Zusammenfassung Bei ausreichender Dosierung ist Reserpin imstande, eine praktisch vollkommene Freisetzung des 5-Oxytryptamins (5-OT) aus den Blutplättchen und der Milz zu verursachen und eine partielle Freisetzung aus der Magen-Darmschleimhaut und dem Gehirn. Die Ausgangswerte werden dann nur langsam erreicht. 5-OT exogener Herkunft hindert die reserpinbedingte Ausschüttung des endogenen 5-OT.     

Inhibition of vaccinia virus multiplication by 2-carboxymethylmercapto-4-amino-5-(p-chlorphenyl)-pyrimidine

Zusammenfassung Mit der Methode der Hemmung der Plaquebildung bei gleichzeitiger Diffusion der antiviralen Stoffe durch den Agar wurde eine hohe Selektivität des 2-Carboxymethylmercapto-4-amino-5(p-chlorphenyl)-pyrimidins für die Hemmung des Vaccinevirus festgestellt. Das Verhältnis der toxischen und der virushemmenden Konzentrationen wurde in den Membrankulturen = 15 gefunden. Die Substanz war gegen andere Viren (NDV, WEE) unwirksam.