AI Article Synopsis

Article Abstract

Aims/hypothesis: Insulin resistance in skeletal muscle is linked to mitochondrial dysfunction in obesity and type 2 diabetes. Emerging evidence indicates that reversible phosphorylation regulates oxidative phosphorylation (OxPhos) proteins. The aim of this study was to identify and quantify site-specific phosphorylation of the catalytic beta subunit of ATP synthase (ATPsyn-beta) and determine protein abundance of ATPsyn-beta and other OxPhos components in skeletal muscle from healthy and insulin-resistant individuals.

Methods: Skeletal muscle biopsies were obtained from lean, healthy, obese, non-diabetic and type 2 diabetic volunteers (each group n = 10) for immunoblotting of proteins, and hypothesis-driven identification and quantification of phosphorylation sites on ATPsyn-beta using targeted nanospray tandem mass spectrometry. Volunteers were metabolically characterised by euglycaemic-hyperinsulinaemic clamps.

Results: Seven phosphorylation sites were identified on ATPsyn-beta purified from human skeletal muscle. Obese individuals with and without type 2 diabetes were characterised by impaired insulin-stimulated glucose disposal rates, and showed a approximately 30% higher phosphorylation of ATPsyn-beta at Tyr361 and Thr213 (within the nucleotide-binding region of ATP synthase) as well as a coordinated downregulation of ATPsyn-beta protein and other OxPhos components. Insulin increased Tyr361 phosphorylation of ATPsyn-beta by approximately 50% in lean and healthy, but not insulin-resistant, individuals.

Conclusions/interpretation: These data demonstrate that ATPsyn-beta is phosphorylated at multiple sites in human skeletal muscle, and suggest that abnormal site-specific phosphorylation of ATPsyn-beta together with reduced content of OxPhos proteins contributes to mitochondrial dysfunction in insulin resistance. Further characterisation of phosphorylation of ATPsyn-beta may offer novel targets of treatment in human diseases with mitochondrial dysfunction, such as diabetes.

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00125-009-1624-0DOI Listing

Publication Analysis

Top Keywords

skeletal muscle
20
phosphorylation atpsyn-beta
16
atp synthase
12
mitochondrial dysfunction
12
phosphorylation
10
atpsyn-beta
10
phosphorylated multiple
8
multiple sites
8
insulin resistance
8
type diabetes
8

Similar Publications

Aerobic exercise (AE) is associated with a significant hypoglycemia risk in individuals with type 1 diabetes mellitus (T1DM). However, the mechanisms in the liver and skeletal muscle governing exercise-induced hypoglycemia in T1DM are poorly understood. This study examined the effects of a 60-minute bout of AE on hepatic and muscle glucose metabolism in T1DM rats.

View Article and Find Full Text PDF

Background: Iliopsoas injuries are a common cause of anterior hip and groin pain and can be successfully managed with conservative treatment. Corticosteroid and local anesthetic injections can also be offered in conjunction with nonoperative management. Given the variability in reported injection guidelines, composition, and techniques, the purpose of this study was to systematically review the literature to assess progression to surgery and patient outcomes following iliopsoas injections.

View Article and Find Full Text PDF

Despite the advances in bionic reconstruction of missing limbs, the control of robotic limbs is still limited and, in most cases, not felt to be as natural by users. In this study, we introduce a control approach that combines robotic design based on postural synergies and neural decoding of synergistic behavior of spinal motoneurons. We developed a soft prosthetic hand with two degrees of actuation that realizes postures in a two-dimensional linear manifold generated by two postural synergies.

View Article and Find Full Text PDF

For trained individuals such as athletes and musicians, learning often plateaus after extensive training, known as the "ceiling effect." One bottleneck to overcome it is having no prior physical experience with the skill to be learned. Here, we challenge this issue by exposing expert pianists to fast and complex finger movements that cannot be performed voluntarily, using a hand exoskeleton robot that can move individual fingers quickly and independently.

View Article and Find Full Text PDF

The prevalence of childhood obesity is increasing worldwide, along with the associated common comorbidities of type 2 diabetes and cardiovascular disease in later life. Motivated by evidence for a strong genetic component, our prior genome-wide association study (GWAS) efforts for childhood obesity revealed 19 independent signals for the trait; however, the mechanism of action of these loci remains to be elucidated. To molecularly characterize these childhood obesity loci, we sought to determine the underlying causal variants and the corresponding effector genes within diverse cellular contexts.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!