Identification of ERAD-dependent degrons for the endoplasmic reticulum lumen.

Degrons are minimal protein features that are sufficient to target proteins for degradation. In most cases, degrons allow recognition by components of the cytosolic ubiquitin proteasome system. Currently, all of the identified degrons only function within the cytosol.

Molecular Visualization of Neuronal TDP43 Pathology .

Nuclear exclusion and cytoplasmic accumulation of the RNA-binding protein TDP43 are characteristic of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Despite this, the origin and ultrastructure of cytosolic TDP43 deposits remain unknown. Accumulating evidence suggests that abnormal RNA homeostasis can drive pathological TDP43 mislocalization, enhancing RNA misprocessing due to loss of nuclear TDP43 and engendering a cycle that ends in cell death.

Identification of ERAD-dependent degrons for the endoplasmic reticulum lumen.

Degrons are minimal protein features that are sufficient to target proteins for degradation. In most cases, degrons allow recognition by components of the cytosolic ubiquitin proteasome system. Currently, all of the identified degrons only function within the cytosol.

Direct observation of autoubiquitination for an integral membrane ubiquitin ligase in ERAD.

The endoplasmic reticulum associated degradation (ERAD) pathway regulates protein quality control at the endoplasmic reticulum. ERAD of lumenal and membrane proteins requires a conserved E3 ubiquitin ligase, called Hrd1. We do not understand the molecular configurations of Hrd1 that enable autoubiquitination and the subsequent retrotranslocation of misfolded protein substrates from the ER to the cytosol.

Deep mutational scanning highlights a role for cytosolic regions in Hrd1 function.

Misfolded endoplasmic reticulum (ER) proteins are degraded through a process called ER-associated degradation (ERAD). Soluble, lumenal ERAD targets are recognized, retrotranslocated across the ER membrane, ubiquitinated, extracted from the membrane, and degraded by the proteasome using an ERAD pathway containing a ubiquitin ligase called Hrd1. To determine how Hrd1 mediates these processes, we developed a deep mutational scanning approach to identify residues involved in Hrd1 function, including those exclusively required for lumenal degradation.

Deep mutational scanning highlights a new role for cytosolic regions in Hrd1 function.

Misfolded endoplasmic reticulum proteins are degraded through a process called endoplasmic reticulum associated degradation (ERAD). Soluble, lumenal ERAD targets are recognized, retrotranslocated across the ER membrane, ubiquitinated, extracted from the membrane, and degraded by the proteasome using an ERAD pathway containing a ubiquitin ligase called Hrd1. To determine how Hrd1 mediates these processes, we developed a deep mutational scanning approach to identify residues involved in Hrd1 function, including those exclusively required for lumenal degradation.

Cycles of autoubiquitination and deubiquitination regulate the ERAD ubiquitin ligase Hrd1.

Misfolded proteins in the lumen of the endoplasmic reticulum (ER) are retrotranslocated into the cytosol and polyubiquitinated before being degraded by the proteasome. The multi-spanning ubiquitin ligase Hrd1 forms the retrotranslocation channel and associates with three other membrane proteins (Hrd3, Usa1, Der1) of poorly defined function. The Hrd1 channel is gated by autoubiquitination, but how Hrd1 escapes degradation by the proteasome and returns to its inactive ground state is unknown.

Tumor Targeting Strategies of Smart Fluorescent Nanoparticles and Their Applications in Cancer Diagnosis and Treatment.

Advantages such as strong signal strength, resistance to photobleaching, tunable fluorescence emissions, high sensitivity, and biocompatibility are the driving forces for the application of fluorescent nanoparticles (FNPs) in cancer diagnosis and therapy. In addition, the large surface area and easy modification of FNPs provide a platform for the design of multifunctional nanoparticles (MFNPs) for tumor targeting, diagnosis, and treatment. In order to obtain better targeting and therapeutic effects, it is necessary to understand the properties and targeting mechanisms of FNPs, which are the foundation and play a key role in the targeting design of nanoparticles (NPs).

Autoubiquitination of the Hrd1 Ligase Triggers Protein Retrotranslocation in ERAD.

Misfolded proteins of the ER are retrotranslocated to the cytosol, where they are polyubiquitinated, extracted from the membrane, and degraded by the proteasome. To investigate how the ER-associated Degradation (ERAD) machinery can accomplish retrotranslocation of a misfolded luminal protein domain across a lipid bilayer, we have reconstituted retrotranslocation with purified S. cerevisiae proteins, using proteoliposomes containing the multi-spanning ubiquitin ligase Hrd1.

Phosphatidylserine flipping enhances membrane curvature and negative charge required for vesicular transport.

Vesicle-mediated protein transport between organelles of the secretory and endocytic pathways is strongly influenced by the composition and organization of membrane lipids. In budding yeast, protein transport between the trans-Golgi network (TGN) and early endosome (EE) requires Drs2, a phospholipid translocase in the type IV P-type ATPase family. However, downstream effectors of Drs2 and specific phospholipid substrate requirements for protein transport in this pathway are unknown.

Type IV P-type ATPases distinguish mono- versus diacyl phosphatidylserine using a cytofacial exit gate in the membrane domain.

Type IV P-type ATPases (P4-ATPases) use the energy from ATP to "flip" phospholipid across a lipid bilayer, facilitating membrane trafficking events and maintaining the characteristic plasma membrane phospholipid asymmetry. Preferred translocation substrates for the budding yeast P4-ATPases Dnf1 and Dnf2 include lysophosphatidylcholine, lysophosphatidylethanolamine, derivatives of phosphatidylcholine and phosphatidylethanolamine containing a 7-nitro-2-1,3-benzoxadiazol-4-yl (NBD) group on the sn-2 C6 position, and were presumed to include phosphatidylcholine and phosphatidylethanolamine species with two intact acyl chains. We previously identified several mutations in Dnf1 transmembrane (TM) segments 1 through 4 that greatly enhance recognition and transport of NBD phosphatidylserine (NBD-PS).

Two-gate mechanism for phospholipid selection and transport by type IV P-type ATPases.

Most P-type ATPases pump specific cations or heavy metals across a membrane to form ion gradients. However, the type IV P-type ATPases evolved the ability to transport specific phospholipid substrates rather than cations and function to establish plasma membrane asymmetry in eukaryotic cells. The mechanism for how a P-type ATPase, or any other transporter, can recognize and flip a phospholipid substrate is unclear.

Identification of residues defining phospholipid flippase substrate specificity of type IV P-type ATPases.

Type IV P-type ATPases (P4-ATPases) catalyze translocation of phospholipid across a membrane to establish an asymmetric bilayer structure with phosphatidylserine (PS) and phosphatidylethanolamine (PE) restricted to the cytosolic leaflet. The mechanism for how P4-ATPases recognize and flip phospholipid is unknown, and is described as the "giant substrate problem" because the canonical substrate binding pockets of homologous cation pumps are too small to accommodate a bulky phospholipid. Here, we identify residues that confer differences in substrate specificity between Drs2 and Dnf1, Saccharomyces cerevisiae P4-ATPases that preferentially flip PS and phosphatidylcholine (PC), respectively.

Phospholipid flippases: building asymmetric membranes and transport vesicles.

Phospholipid flippases in the type IV P-type ATPase family (P4-ATPases) are essential components of the Golgi, plasma membrane and endosomal system that play critical roles in membrane biogenesis. These pumps flip phospholipid across the bilayer to create an asymmetric membrane structure with substrate phospholipids, such as phosphatidylserine and phosphatidylethanolamine, enriched within the cytosolic leaflet. The P4-ATPases also help form transport vesicles that bud from Golgi and endosomal membranes, thereby impacting the sorting and localization of many different proteins in the secretory and endocytic pathways.

P3a amplitude predicts successful treatment program completion in substance-dependent individuals.

This study examined P3a amplitude as a direct predictor of treatment success for substance dependence. Participants were 35 adults (27 men, 8 women) undergoing treatment for substance dependence at an urban residential treatment facility between October 2005 and July 2007. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) criteria were used to confirm substance dependence.

Association of P3 amplitude to treatment completion in substance dependent individuals.

Individuals with substance use disorders typically show reduced amplitudes of the P3 component of the evoked potential and high scores on impulsivity and aggression measures. The present study investigated the usefulness of P3 amplitude, addiction severity and impulsivity as predictors of treatment completion in substance dependence. Forty-four participants (8 women), between the ages of 19 and 61 years old, who met DSM-IV-TR Axis I substance/alcohol dependence criteria were recruited for the present study.

Pharmacologic treatment of impulsive aggression with antiepileptic drugs.

Aggressive behavior is a major concern in mental health and criminal justice settings. Although pharmacotherapy is often used in the treatment of the violent individual, no medication is presently approved by the US Food and Drug Administration specifically for such use. In recent years, antiepileptic drugs (AEDs) have become increasingly popular for the management of impulsive (reactive) aggressive behavior.

Enhanced intensity dependence and aggression history indicate previous regular ecstasy use in abstinent polydrug users.

Intensity dependence is an electrophysiological measure of intra-individual stability of the augmenting/reducing characteristic of N1/ P2 event-related potential amplitudes in response to stimuli of varying intensities. Abstinent ecstasy users typically show enhanced intensity dependence and higher levels of impulsivity and aggression. Enhanced intensity dependence and high impulsivity and aggression levels may be due to damage in the brain's serotonergic neurons as a result of ecstasy use.

Comparison of impulsive and premeditated perpetrators of intimate partner violence.

Violence occurs in four to five million intimate relationships each year in the United States. Past research has investigated the concept of batterer subtypes based on the nature of the violent behavior. To extend this research, the present study used the Impulsive/Premeditated Aggression Scale (IPAS) along with a battery of relevant self-report measures in a sample of men (N = 113) convicted of domestic violence and court ordered into an intervention program.

Investigation of nocturnal oviposition by necrophilous flies in central Texas.

The need to accurately estimate the postmortem interval (PMI) has prompted research into factors affecting fly oviposition (i.e., oviposition and/or larviposition) on a corpse.

Development and content validation of family practice residency recruitment questionnaires.

Background And Objectives: The residency recruitment process involves a substantial time and financial commitment on the part of medical students and residency programs. This paper describes the development and content validation process of two written questionnaires designed to assess the application and interview process at our family practice residency program.

Methods: Two written questionnaires were developed after completion of a literature review and from areas deemed important by our academic faculty.

Photosensitization of Eretmapodites quinquevittatus Theobald (Diptera: Culicidae) eggs and larvae with Photofrin II.

The susceptibility of Eretmapodites quinquevittatus eggs and larvae to photosensitization with Photofrin II (PII) was determined. Hatching rates of eggs (5 min to 2 h after oviposition with no PII exposure) exposed to solutions of PII (90 micrograms/ml) in the dark for 12 h, before photoirradiation for 72 h. were very similar to those of untreated controls (P > 0.