Background: Genetic disorders contribute to significant morbidity and mortality in critically ill newborns. Despite advances in genome sequencing technologies, a majority of neonatal cases remain unsolved. Complex structural variants (SVs) often elude conventional genome sequencing variant calling pipelines and will explain a portion of these unsolved cases.
View Article and Find Full Text PDFRapid whole genome sequencing (rapid WGS) is a powerful diagnostic tool that is becoming increasingly practical for widespread clinical use. However, protocols for its use are challenging to implement. A significant obstacle to clinical adoption is that laboratory certification requires an initial research development phase, which is constrained by regulations from returning results.
View Article and Find Full Text PDFThe genetic architecture of atrial fibrillation (AF) encompasses low impact, common genetic variants and high impact, rare variants. Here, we characterize a high impact AF-susceptibility allele, KCNQ1 R231H, and describe its transcontinental geographic distribution and history. Induced pluripotent stem cell-derived cardiomyocytes procured from risk allele carriers exhibit abbreviated action potential duration, consistent with a gain-of-function effect.
View Article and Find Full Text PDFThe cellular ESCRT (endosomal sorting complexes required for transport) pathway drives membrane constriction toward the cytosol and effects membrane fission during cytokinesis, endosomal sorting, and the release of many enveloped viruses, including the human immunodeficiency virus. A component of this pathway, the AAA ATPase Vps4, provides energy for pathway progression. Although it is established that Vps4 functions as an oligomer, subunit stoichiometry and other fundamental features of the functional enzyme are unclear.
View Article and Find Full Text PDFThe ESCRT pathway helps mediate the final abscission step of cytokinesis in mammals and archaea. In mammals, two early acting proteins of the ESCRT pathway, ALIX and TSG101, are recruited to the midbody through direct interactions with the phosphoprotein CEP55. CEP55 resides at the centrosome through most of the cell cycle but then migrates to the midbody at the start of cytokinesis, suggesting that the ESCRT pathway may also have centrosomal links.
View Article and Find Full Text PDFThe ESCRT (endosomal sorting complex required for transport) pathway is required for terminal membrane fission events in several important biological processes, including endosomal intraluminal vesicle formation, HIV budding and cytokinesis. VPS4 ATPases perform a key function in this pathway by recognizing membrane-associated ESCRT-III assemblies and catalysing their disassembly, possibly in conjunction with membrane fission. Here we show that the microtubule interacting and transport (MIT) domains of human VPS4A and VPS4B bind conserved sequence motifs located at the carboxy termini of the CHMP1-3 class of ESCRT-III proteins.
View Article and Find Full Text PDFThe outer mitochondrial membrane protein Ugo1 forms a complex with the Fzo1p and Mgm1p GTPases that regulates mitochondrial fusion in yeast. Ugo1p contains two putative carrier domains (PCDs) found in mitochondrial carrier proteins (MCPs). Mitochondrial carrier proteins are multipass transmembrane proteins that actively transport molecules across the inner mitochondrial membrane.
View Article and Find Full Text PDFInteractions between yeast Dnm1p, Mdv1p, and Fis1p are required to form fission complexes that catalyze division of the mitochondrial compartment. During the formation of mitochondrial fission complexes, the Dnm1p GTPase self-assembles into large multimeric complexes on the outer mitochondrial membrane that are visualized as punctate structures by fluorescent labeling. Although it is clear that Fis1p.
View Article and Find Full Text PDFMitochondrial division requires coordinated interactions among Fis1p, Mdv1p, and the Dnm1p GTPase, which assemble into fission complexes on the outer mitochondrial membrane. The integral outer membrane protein Fis1p contains a cytoplasmic domain consisting of a tetratricopeptide repeat (TPR)-like fold and a short NH(2)-terminal helix. Although it is known that the cytoplasmic domain is necessary for assembly of Mdv1p and Dnm1p into fission complexes, the molecular details of this assembly are not clear.
View Article and Find Full Text PDF