Formation of I+III supercomplex rescues respiratory chain defects.

Mitochondrial electron transport chain (ETC) complexes partition between free complexes and quaternary assemblies known as supercomplexes (SCs). However, the physiological requirement for SCs and the mechanisms regulating their formation remain controversial. Here, we show that genetic perturbations in mammalian ETC complex III (CIII) biogenesis stimulate the formation of a specialized extra-large SC (SC-XL) with a structure of I+III, resolved at 3.

Mitochondrial microproteins link metabolic cues to respiratory chain biogenesis.

Electron transport chain (ETC) biogenesis is tightly coupled to energy levels and availability of ETC subunits. Complex III (CIII), controlling ubiquinol:ubiquinone ratio in ETC, is an attractive node for modulating ETC levels during metabolic stress. Here, we report the discovery of mammalian Co-ordinator of mitochondrial CYTB (COM) complexes that regulate the stepwise CIII biogenesis in response to nutrient and nuclear-encoded ETC subunit availability.

Hip Hemiarthroplasty: The Misnomer of a Narrow Femoral Canal and the Cost Implications.

Objective Hemiarthroplasty has been identified as the treatment of choice for displaced intracapsular femoral neck fractures. A modular prosthesis is sometimes preferred for its sizing options in narrow femoral canals, despite its higher cost and no advantage in clinical outcomes. Thus, in this study, we investigated the factors affecting surgeons' choice of prosthesis, hypothesizing that modular hemiarthroplasty is overused for narrow femoral canals compared to monoblock hip hemiarthroplasty.