Disease Phenotypes and Mechanisms of iPSC-Derived Cardiomyocytes From Brugada Syndrome Patients With a Loss-of-Function SCN5A Mutation.

Brugada syndrome (BrS) is one of the major causes of sudden cardiac death in young people, while the underlying mechanisms are not completely understood. Here, we investigated the pathophysiological phenotypes and mechanisms using induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CMs) from two BrS patients (BrS-CMs) carrying a heterozygous mutation p.S1812X.

Ultrasonic-augmented Primary Adult Fibroblast Isolation.

Primary adult fibroblasts have become an important tool to study fibrosis, fibroblast interactions and inflammation in all body tissues. Since primary fibroblasts cannot divide indefinitely due to myofibroblast differentiation or senescence induction, new cultures must be established regularly. However, there are several obstacles to overcome during the processes of developing a reliable isolation protocol and primary fibroblast isolation itself: the method's degree of difficulty (especially for beginners), the risk of bacterial contamination, the required time until primary fibroblasts can be used for experiments, and subsequent cell quality and viability.

Lipidomic Changes in Skeletal Muscle in Patients after Biliopancreatic Diversion.

The mechanisms behind the fast improvements of insulin sensitivity and release of the diabetic metabolic state after bariatric surgery are still not completely understood. To further elucidate the effects on the individual cellular level, we applied mass spectrometry to investigate the changes in the lipidomic profile of skeletal muscle cells before and after biliopancreatic diversion in six patients. We found a decrease in lipid storage species, mainly triacylglycerides (e.

The mitochondrial ADP/ATP carrier associates with the inner membrane presequence translocase in a stoichiometric manner.

The majority of mitochondrial proteins are synthesized with amino-terminal signal sequences. The presequence translocase of the inner membrane (TIM23 complex) mediates the import of these preproteins. The essential TIM23 core complex closely cooperates with partner protein complexes like the presequence translocase-associated import motor and the respiratory chain.

Mitochondrial inner membrane protease promotes assembly of presequence translocase by removing a carboxy-terminal targeting sequence.

The presequence translocase of the inner mitochondrial membrane (TIM23 complex) is essential for importing cleavable preproteins into mitochondria. The preproteins contain amino-terminal targeting sequences that are removed by the mitochondrial processing peptidase (MPP). Some preproteins carry bipartite presequences that are cleaved twice, by MPP and the inner membrane protease (IMP).

Mgr2 promotes coupling of the mitochondrial presequence translocase to partner complexes.

Many mitochondrial proteins are synthesized with N-terminal presequences in the cytosol. The presequence translocase of the inner mitochondrial membrane (TIM23) translocates preproteins into and across the membrane and associates with the matrix-localized import motor. The TIM23 complex consists of three core components and Tim21, which interacts with the translocase of the outer membrane (TOM) and the respiratory chain.

Distinct forms of mitochondrial TOM-TIM supercomplexes define signal-dependent states of preprotein sorting.

Mitochondrial import of cleavable preproteins occurs at translocation contact sites, where the translocase of the outer membrane (TOM) associates with the presequence translocase of the inner membrane (TIM23) in a supercomplex. Different views exist on the mechanism of how TIM23 mediates preprotein sorting to either the matrix or inner membrane. On the one hand, two TIM23 forms were proposed, a matrix transport form containing the presequence translocase-associated motor (PAM; TIM23-PAM) and a sorting form containing Tim21 (TIM23(SORT)).