Vimentin regulates nuclear segmentation in neutrophils
Jiaqi Liu,
Zhixun Li,
Meijing Li
et al.
Abstract:Granulocytes are indispensable for various immune responses. Unlike other cell types in the body, the nuclei of granulocytes, particularly neutrophils, are heavily segmented into multiple lobes. Although this distinct morphological feature has long been observed, the underlying mechanism remains incompletely characterized. In this study, we utilize cryo-electron tomography to examine the nuclei of mouse neutrophils, revealing the cytoplasmic enrichment of intermediate filaments on the concave regions of the nu… Show more
Mitochondrial plasticity, coordinated by fission and fusion, is crucial to ensure cellular functions. Mitochondrial fission is mediated by the GTPase Drp1 at the constriction site, which is proposed to be driven by the actin-myosin contractile force. However, the mechanism that propels constriction remains unclear, and the potential involvement of additional mechanisms in this process remains an open question. Here, using structured illumination microscopy and electron microscopy, we show that the type-III intermediate filament glial fibrillary acidic protein (GFAP) closely surrounds mitochondria fission sites and associates with accumulated Drp1 molecules. Remarkably, loss of GFAP results in hyperfused mitochondria under physiological condition and even Ca2+-induced mitochondrial fission. Additionally, mutations of GFAP, the cause of Alexander disease, result in an elevated recruitment of Drp1 to GFAP, leading to significantly increased mitochondrial fissions. Taking together, these findings suggest a novel mechanism of mitochondrial division mediated by type-III intermediate filaments.
Mitochondrial plasticity, coordinated by fission and fusion, is crucial to ensure cellular functions. Mitochondrial fission is mediated by the GTPase Drp1 at the constriction site, which is proposed to be driven by the actin-myosin contractile force. However, the mechanism that propels constriction remains unclear, and the potential involvement of additional mechanisms in this process remains an open question. Here, using structured illumination microscopy and electron microscopy, we show that the type-III intermediate filament glial fibrillary acidic protein (GFAP) closely surrounds mitochondria fission sites and associates with accumulated Drp1 molecules. Remarkably, loss of GFAP results in hyperfused mitochondria under physiological condition and even Ca2+-induced mitochondrial fission. Additionally, mutations of GFAP, the cause of Alexander disease, result in an elevated recruitment of Drp1 to GFAP, leading to significantly increased mitochondrial fissions. Taking together, these findings suggest a novel mechanism of mitochondrial division mediated by type-III intermediate filaments.
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