Cell-free expression with a quartz crystal microbalance enables rapid, dynamic, and label-free characterization of membrane-interacting proteins.

Integral and interacting membrane proteins (IIMPs) constitute a vast family of biomolecules that perform essential functions in all forms of life. However, characterizing their interactions with lipid bilayers remains limited due to challenges in purifying and reconstituting IIMPs in vitro or labeling IIMPs without disrupting their function in vivo. Here, we report cell-free transcription-translation in a quartz crystal microbalance with dissipation (TXTL-QCMD) to dynamically characterize interactions between diverse IIMPs and membranes without protein purification or labeling. As part of TXTL-QCMD, IIMPs are synthesized using cell-free transcription-translation (TXTL), and their interactions with supported lipid bilayers are measured using a quartz crystal microbalance with dissipation (QCMD). TXTL-QCMD reconstitutes known IIMP-membrane dependencies, including specific association with prokaryotic or eukaryotic membranes, and the multiple-IIMP dynamical pattern-forming association of the E. coli division-coordinating proteins MinCDE. Applying TXTL-QCMD to the recently discovered Zorya anti-phage system that is unamenable to labeling, we discovered that ZorA and ZorB integrate within the lipids found at the poles of bacteria while ZorE diffuses freely on the non-pole membrane. These efforts establish the potential of TXTL-QCMD to broadly characterize the large diversity of IIMPs.

The elephant trunk: a rare morphology of the left atrial appendage-a case report.

Background: Patients with atrial fibrillation (AF) are at increased risk for thromboembolic events including stroke. The primary source for thromboembolism in these patients is thrombus formation in the left atrial appendage (LAA). Depending on the individual thromboembolic risk, long-term anticoagulation is recommended. In certain patients, however, long-term anticoagulation is contraindicated, and interventional closure of the LAA (LAAC) represents an alternative approach to lower the thromboembolic risk and avoid oral anticoagulation. Case summary: An 83-year-old male underwent LAAC at our centre in November 2022. Prior to the procedure, a thrombus in the left atrium (LA) or LAA was excluded by transoesophageal echocardiography (TOE), and the anatomy of the LAA was assessed as eligible for LAAC with no evidence of anatomical irregularities. After contrast medium injection, angiography revealed an atypical anatomic variant of the LAA with a substantially long, elephant trunk-like course. Discussion: We present a previously not described unique anatomic variant of the LAA: the elephant trunk morphology. Left atrial appendage anatomy is very heterogeneous, and detailed knowledge of LAA morphology is important for endovascular LAA procedures as well as for predicting the risk of thromboembolic events. Despite thorough pre-procedural imaging, anatomic variants may remain obscured.

The interplay between autophagy and cGAS-STING signaling and its implications for cancer.

Autophagy is an intracellular process that targets various cargos for degradation, including members of the cGAS-STING signaling cascade. cGAS-STING senses cytosolic double-stranded DNA and triggers an innate immune response through type I interferons. Emerging evidence suggests that autophagy plays a crucial role in regulating and fine-tuning cGAS-STING signaling. Reciprocally, cGAS-STING pathway members can actively induce canonical as well as various non-canonical forms of autophagy, establishing a regulatory network of feedback mechanisms that alter both the cGAS-STING and the autophagic pathway. The crosstalk between autophagy and the cGAS-STING pathway impacts a wide variety of cellular processes such as protection against pathogenic infections as well as signaling in neurodegenerative disease, autoinflammatory disease and cancer. Here we provide a comprehensive overview of the mechanisms involved in autophagy and cGAS-STING signaling, with a specific focus on the interactions between the two pathways and their importance for cancer.