Phase separation of an actin nucleator by junctional microtubules regulates epithelial function

Liquid-liquid phase separation (LLPS) is involved in various dynamic biological phenomena. In epithelial cells, dynamic regulation of junctional actin filaments tethered to the apical junctional complex (AJC) is critical for maintaining internal homeostasis against external perturbations; however, the role of LLPS in this process remains unknown. Here, after identifying a multifunctional actin nucleator, cordon bleu (Cobl), as an AJC-enriched microtubule-associated protein, we conducted comprehensive in vitro and in vivo analyses. We found that apical microtubules promoted LLPS of Cobl at the AJC, and Cobl actin assembly activity increased upon LLPS. Thus, microtubules spatiotemporally regulated junctional actin assembly for epithelial morphogenesis and paracellular barriers. Collectively, these findings established that LLPS of the actin nucleator Cobl mediated dynamic microtubule-actin cross-talk in junctions, which fine-tuned the epithelial barrier

Transesophageal echocardiography for cardiac herniation occurring during robotic-assisted mitral valve repair: a case report

Abstract Background Cardiac herniation has been reported in thoracic trauma and after pneumonectomy; however, it is sporadic in cardiac surgery. Case presentation A 35-year-old male patient underwent an elective totally endoscopic robotic-assisted mitral valve repair (TERMVR). His hemodynamics were stable after weaning from cardiopulmonary bypass, and no residual mitral valve regurgitation was observed. However, during suturing of the port wound, the patient developed hypotension, which improved with phenylephrine administration. Four-chamber transesophageal echocardiography (TEE) images showed cardiac deformity, and postoperative chest radiography confirmed the dextrocardia. The cardiac herniation was repaired by deflating the left lung and over-inflating the right lung using a double-lumen tube, allowing selective ventilation without re-thoracotomy. The patient was discharged on the sixth postoperative day without complications. Conclusions This was a very unusual case of cardiac herniation during TERMVR visualized using distinct TEE images. The cardiac herniation was successfully repaired using a double-lumen tube without re-thoracotomy

Dominant-negative Effects of the N-terminal Half of Prion Protein on Neurotoxicity of Prion Protein-like Protein/Doppel in Mice*

Prion protein-like protein/doppel is neurotoxic, causing ataxia and Purkinje cell degeneration in mice, whereas prion protein antagonizes doppel-induced neurodegeneration. Doppel is homologous to the C-terminal half of prion protein but lacks the amino acid sequences corresponding to the N-terminal half of prion protein. We show here that transgenic mice expressing a fusion protein consisting of the N-terminal half, corresponding to residues 1-124, of prion protein and doppel in neurons failed to develop any neurological signs for up to 730 days in a background devoid of prion protein. In addition, the fusion protein prolonged the onset of ataxia in mice expressing exogenous doppel. These results suggested that the N-terminal part of prion protein has a neuroprotective potential acting both cis and trans on doppel. We also show that prion protein lacking the pre-octapeptide repeat (Δ25-50) or octapeptide repeat (Δ51-90) region alone could not impair the antagonistic function against doppel