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Human Tim8a and Tim8b are paralogous intermembrane space proteins of the small TIM chaperone family. Yeast small TIMs function in the trafficking of proteins to the outer and inner mitochondrial membranes. This putative import function for hTim8a and hTim8b has been challenged in human models, but their precise molecular function(s) remains undefined. Likewise, the necessity for human cells to encode two Tim8 proteins and whether any potential redundancy exists is unclear. We demonstrate that hTim8a and hTim8b function in the assembly of cytochrome c oxidase (Complex IV). Using affinity enrichment mass spectrometry, we define the interaction network of hTim8a, hTim8b and hTim13, identifying subunits and assembly factors of the Complex IV COX2 module. hTim8‐deficient cells have a COX2 and COX3 module defect and exhibit an accumulation of the Complex IV S2 subcomplex. These data suggest that hTim8a and hTim8b function in assembly of Complex IV via interactions with intermediate‐assembly subcomplexes. We propose that hTim8–hTim13 complexes are auxiliary assembly factors involved in the formation of the Complex IV S3 subcomplex during assembly of mature Complex IV.

Infection with Plasmodium falciparum parasites results in approximately 627,000 deaths from malaria annually. Key to the parasite's success is their ability to invade and subsequently grow within human erythrocytes. Parasite proteins involved in parasite invasion and proliferation are therefore intrinsically of great interest, as targeting these proteins could provide novel means of therapeutic intervention. One such protein is P113 which has been reported to be both an invasion protein and an intracellular protein located within the parasitophorous vacuole (PV). The PV is delimited by a membrane (PVM) across which a plethora of parasite-specific proteins are exported via the Plasmodium Translocon of Exported proteins (PTEX) into the erythrocyte to enact various immune evasion functions. To better understand the role of P113 we isolated its binding partners from in vitro cultures of P. falciparum. We detected interactions with the protein export machinery (PTEX and exported protein-interacting complex) and a variety of proteins that either transit through the PV or reside on the parasite plasma membrane. Genetic knockdown or partial deletion of P113 did not significantly reduce parasite growth or protein export but did disrupt the morphology of the PVM, suggesting that P113 may play a role in maintaining normal PVM architecture.

OBJECTIVE: Fixed ratio blood product administration may improve outcomes in trauma patients with massive blood loss. The present study aimed to describe the impact of a major haemorrhage protocol (MHP) on the ratio of blood products administered for paediatric major trauma. METHODS: Retrospective observational study in a state-designated paediatric major trauma centre in Melbourne, Australia. Children with major trauma who received blood products in the ED were identified from a hospital trauma registry. Blood product ratios before, during and after implementation of a hospital MHP were compared in consecutive 2 year blocks. RESULTS: Over a 6 year period, 767 major trauma patients were identified, of whom 47 received blood products in the ED and were included in the analysis; 14 pre-MHP implementation, 24 during-MHP implementation and nine post-MHP implementation. No patients received blood products at a ratio of 1:1:1 for red blood cells:fresh frozen plasma:platelets, respectively, during any time period. In this cohort of predominantly blunt trauma, blood products were infrequently administered in the ED because of the low prevalence of massive blood loss. Coagulopathy and hypofibrinogenaemia were commonly observed, nearly half of included patients were managed operatively and one quarter did not survive their injuries. CONCLUSION: The implementation of a MHP did not change the ratio of blood product administration in this cohort of patients because of the infrequency of massive blood loss. Future studies may focus on the impact of treating coagulopathy and hypofibrinogenaemia on patient-centred outcomes.

The majority of proteins localised to mitochondria are encoded by the nuclear genome, with approximately 1500 proteins imported into mammalian mitochondria. Dysfunction in this fundamental cellular process is linked to a variety of pathologies including neuropathies, cardiovascular disorders, myopathies, neurodegenerative diseases and cancer, demonstrating the importance of mitochondrial protein import machinery for cellular function. Correct import of proteins into mitochondria requires the co-ordinated activity of multimeric protein translocation and sorting machineries located in both the outer and inner mitochondrial membranes, directing the imported proteins to the destined mitochondrial compartment. This dynamic process maintains cellular homeostasis, and its dysregulation significantly affects cellular signalling pathways and metabolism. This review summarises current knowledge of the mammalian mitochondrial import machinery and the pathological consequences of mutation of its components. In addition, we will discuss the role of mitochondrial import in cancer, and our current understanding of the role of mitochondrial import in neurodegenerative diseases including Alzheimer's disease, Huntington's disease and Parkinson's disease.

OBJECTIVE: Thoracic trauma is a leading cause of paediatric trauma deaths. Traumatic cardiac arrest, tension pneumothorax and massive haemothorax are life-threatening conditions requiring emergency and definitive pleural decompression. In adults, thoracostomy is increasingly preferred over needle thoracocentesis for emergency pleural decompression. The present study reports on the early experience of thoracostomy in children, to inform debate regarding the best approach for emergency pleural compression in paediatric trauma. METHODS: Retrospective review of Ambulance Victoria and The Royal Children's Hospital Melbourne, Trauma Registry between August 2016 and February 2019 to identify children undergoing thoracostomy for trauma, either pre-hospital or in the ED. RESULTS: Fourteen children aged 1.2-15 years underwent 23 thoracostomy procedures over the 31 month period. The majority of patients sustained transport-related injuries, and underwent thoracostomies for the primary indications of hypoxia and hypotension. Two children were in traumatic cardiac arrest. Ten children underwent needle thoracocentesis prior to thoracostomy, but all required thoracostomy to achieve the necessary definitive decompression. All patients were severely injured with multiple-associated serious injuries and median Injury Severity Score 35.5 (17-75), three of whom died from their injuries. Thoracostomy in our cohort had a low complication rate. CONCLUSION: In severely injured children, thoracostomy is an effective and reliable method to achieve emergency pleural decompression, including in the young child. The technical challenges presented by children are real, but can be addressed by training to support a low complication rate. We recommend thoracostomy over needle thoracocentesis as the first-line intervention in children with traumatic cardiac arrest, tension pneumothorax and massive haemothorax. [Correction added on 23 September 2019 after first online publication: in the second sent

It is now clear that access to specific metabolic programmes controls the survival and function of various immune cell populations, including T cells. Efficient naïve and memory T cell homoeostasis requires the use of specific metabolic pathways and differentiation requires rapid and dramatic metabolic remodelling. While we are beginning to appreciate the crucial role of metabolic programming during normal T cell physiology, many of the potential impacts of ageing on metabolic homoeostasis and remodelling in T cells remain unexplored. This review will outline our current understanding of T cell metabolism and explore age-related metabolic changes that are postulated or have been demonstrated to impact T cell function.

Plasmodium falciparum, which causes malaria, extensively remodels its human host cells, particularly erythrocytes. Remodelling is essential for parasite survival by helping to avoid host immunity and assisting in the uptake of plasma nutrients to fuel rapid growth. Host cell renovation is carried out by hundreds of parasite effector proteins that are exported into the erythrocyte across an enveloping parasitophorous vacuole membrane (PVM). The Plasmodium translocon for exported (PTEX) proteins is thought to span the PVM and provide a channel that unfolds and extrudes proteins across the PVM into the erythrocyte. We show that exported reporter proteins containing mouse dihydrofolate reductase domains that inducibly resist unfolding become trapped at the parasite surface partly colocalizing with PTEX. When cargo is trapped, loop-like extensions appear at the PVM containing both trapped cargo and PTEX protein EXP2, but not additional components HSP101 and PTEX150. Following removal of the block-inducing compound, export of reporter proteins only partly recovers possibly because much of the trapped cargo is spatially segregated in the loop regions away from PTEX. This suggests that parasites have the means to isolate unfoldable cargo proteins from PTEX-containing export zones to avert disruption of protein export that would reduce parasite growth.