Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 5 de 5
Filter
Add more filters










Database
Language
Publication year range
1.
Cureus ; 15(5): e39041, 2023 May.
Article in English | MEDLINE | ID: mdl-37378216

ABSTRACT

Henoch-Schönlein purpura (HSP) or IgA vasculitis is a small-vessel vasculitis mediated by IgA deposition, often associated with upper respiratory tract infection and family history. However, there is a rare correlation to human leukocyte antigen (HLA) B27 arthropathy. We present a case of a young boy diagnosed with HSP suffering from arthritis, gait disturbance, and weakness throughout childhood, ultimately diagnosed with ankylosing spondylitis and sacroiliitis clinically, with confirmation through X-ray and supporting HLA B27 testing.

2.
Cureus ; 15(5): e39074, 2023 May.
Article in English | MEDLINE | ID: mdl-37323356

ABSTRACT

Foreign body aspiration is of significant prevalence in the pediatric and young adult populations. After dental work, patients are more likely to develop pulmonary symptoms secondary to aspiration events within the tracheobronchial tree. Herein, we describe the clinical case of a 22-year-old man with a past medical history of epilepsy and tuberous sclerosis who presented to his primary care provider for chronic coughing and wheezing. With symptoms refractory to albuterol and control of allergies, radiography was obtained, revealing a 4.1 cm dental product in the right bronchus. We provide an overview of our retrieval method as well as a comparison of flexible and rigid bronchoscopies and the bronchoscopic tools available.

3.
Sci Rep ; 9(1): 14506, 2019 10 10.
Article in English | MEDLINE | ID: mdl-31601863

ABSTRACT

The ubiquitin-proteasome system (UPS) is responsible for the bulk of protein degradation in eukaryotic cells, but the factors that cause different substrates to be unfolded and degraded to different extents are still poorly understood. We previously showed that polyubiquitinated substrates were degraded with greater processivity (with a higher tendency to be unfolded and degraded than released) than ubiquitin-independent substrates. Thus, even though ubiquitin chains are removed before unfolding and degradation occur, they affect the unfolding of a protein domain. How do ubiquitin chains activate the proteasome's unfolding ability? We investigated the roles of the three intrinsic proteasomal ubiquitin receptors - Rpn1, Rpn10 and Rpn13 - in this activation. We find that these receptors are required for substrate-mediated activation of the proteasome's unfolding ability. Rpn13 plays the largest role, but there is also partial redundancy between receptors. The architecture of substrate ubiquitination determines which receptors are needed for maximal unfolding ability, and, in some cases, simultaneous engagement of ubiquitin by multiple receptors may be required. Our results suggest physical models for how ubiquitin receptors communicate with the proteasomal motor proteins.


Subject(s)
Proteasome Endopeptidase Complex/genetics , Proteolysis , Ubiquitin/genetics , Ubiquitination/genetics , Cytoplasm/genetics , Cytoplasm/metabolism , DNA-Binding Proteins/genetics , Intracellular Signaling Peptides and Proteins/genetics , Protein Unfolding , RNA-Binding Proteins/genetics , Substrate Specificity
4.
J Biol Chem ; 291(35): 18547-61, 2016 08 26.
Article in English | MEDLINE | ID: mdl-27405762

ABSTRACT

In eukaryotic cells, proteins are targeted to the proteasome for degradation by polyubiquitination. These proteins bind to ubiquitin receptors, are engaged and unfolded by proteasomal ATPases, and are processively degraded. The factors determining to what extent the proteasome can successfully unfold and degrade a substrate are still poorly understood. We find that the architecture of polyubiquitin chains attached to a substrate affects the ability of the proteasome to unfold and degrade the substrate, with K48- or mixed-linkage chains leading to greater processivity than K63-linked chains. Ubiquitin-independent targeting of substrates to the proteasome gave substantially lower processivity of degradation than ubiquitin-dependent targeting. Thus, even though ubiquitin chains are removed early in degradation, during substrate engagement, remarkably they dramatically affect the later unfolding of a protein domain. Our work supports a model in which a polyubiquitin chain associated with a substrate switches the proteasome into an activated state that persists throughout the degradation process.


Subject(s)
Models, Biological , Polyubiquitin/chemistry , Proteasome Endopeptidase Complex/chemistry , Protein Unfolding , Proteolysis , Ubiquitination , Humans , Polyubiquitin/genetics , Polyubiquitin/metabolism , Proteasome Endopeptidase Complex/genetics , Proteasome Endopeptidase Complex/metabolism
5.
IUBMB Life ; 66(5): 309-17, 2014 May.
Article in English | MEDLINE | ID: mdl-24823973

ABSTRACT

ATP-dependent proteases are present in all organisms, where they are responsible for much of intracellular protein degradation. Most proteins are processively unfolded and degraded into small peptides; however, in a few so-called slippery substrates, the protease stalls at a folded domain and releases a large protein fragment. In this review, we describe the properties of physiological slippery substrates that are processed in this manner by ATP-dependent proteases and the recent advances that have been made in understanding the mechanism underlying their partial degradation.


Subject(s)
ATP-Dependent Proteases/physiology , Proteolysis , ATP-Dependent Proteases/chemistry , Animals , Bacterial Proteins/chemistry , Bacterial Proteins/physiology , Humans , Peptide Fragments/metabolism , Proteasome Endopeptidase Complex/chemistry , Proteasome Endopeptidase Complex/physiology , Protein Structure, Tertiary , Ubiquitinated Proteins/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL
...