RESUMO
Filopodia are peripheral F-actin-rich structures that enable cell sensing of the microenvironment. Fascin is an F-actin-bundling protein that plays a key role in stabilizing filopodia to support efficient adhesion and migration. Fascin is also highly up-regulated in human cancers, where it increases invasive cell behavior and correlates with poor patient prognosis. Previous studies have shown that fascin phosphorylation can regulate F-actin bundling, and that this modification can contribute to subcellular fascin localization and function. However, the factors that regulate fascin dynamics within filopodia remain poorly understood. In the current study, we used advanced live-cell imaging techniques and a fascin biosensor to demonstrate that fascin phosphorylation, localization, and binding to F-actin are highly dynamic and dependent on local cytoskeletal architecture in cells in both 2D and 3D environments. Fascin dynamics within filopodia are under the control of formins, and in particular FMNL2, that binds directly to dephosphorylated fascin. Our data provide new insight into control of fascin dynamics at the nanoscale and into the mechanisms governing rapid cytoskeletal adaptation to environmental changes. This filopodia-driven exploration stage may represent an essential regulatory step in the transition from static to migrating cancer cells.
Assuntos
Actinas/genética , Proteínas de Transporte/genética , Forminas/genética , Proteínas dos Microfilamentos/genética , Neoplasias/genética , Pseudópodes/genética , Técnicas Biossensoriais , Proteínas de Transporte/isolamento & purificação , Adesão Celular/genética , Movimento Celular/genética , Microambiente Celular/genética , Células HeLa , Humanos , Proteínas dos Microfilamentos/isolamento & purificação , Imagem Molecular , Neoplasias/patologia , Fosforilação , Ligação Proteica/genética , Pseudópodes/metabolismoRESUMO
The authors have now instituted the paddle-wheel method of CT reconstruction imaging of the lungs as a routine supplement to the standard axial multislice helical CT pulmonary angiography images for pulmonary embolism, and are exploring its role in other diseases. This unique way of viewing lung structures adds a new dimension to pulmonary imaging. Large-scale comparison studies of the traditional and the proposed paddle-wheel CT display method are necessary to quantitate their relative clinical effectiveness in the evaluation of the pulmonary vasculature, airways, and lungs.
Assuntos
Pneumopatias/diagnóstico por imagem , Pulmão/anatomia & histologia , Pulmão/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Humanos , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Pulmão/irrigação sanguínea , Artéria Pulmonar/diagnóstico por imagem , Circulação Pulmonar , Radiografia TorácicaRESUMO
In five patients with acute multilobar pulmonary embolism (PE) who were imaged with multi-detector row CT angiography, maximum intensity projection images were reformatted from axial images into rotated paddlewheel and coronal planes with three slab thicknesses and were reviewed for evidence of PE on a per-vessel basis with consensus of two readers. Paddlewheel reformations had a significantly higher percentage of overall detection of PE than did coronal reformations obtained with equivalent slab thickness (P <.0001). Paddlewheel reformations with 5.0-mm slab thickness had no significantly different percentage of overall detection of PE compared with that of axial images obtained with 2.5-mm collimation.