Endothelial exocytosis of Weibel-Palade body (WPB) is one of the first lines of defence against vascular injury. However, the mechanisms that control WPB exocytosis in the final stages (including the docking, priming and fusion of granules) are poorly understood. Here we show that the focal adhesion protein zyxin is crucial in this process. Zyxin downregulation inhibits the secretion of von Willebrand factor (VWF), the most abundant cargo in WPBs, from human primary endothelial cells (ECs) induced by cAMP agonists. Zyxin-deficient mice exhibit impaired epinephrine-stimulated VWF release, prolonged bleeding time and thrombosis, largely due to defective endothelial secretion of VWF. Using live-cell super-resolution microscopy, we visualize previously unappreciated reorganization of pre-existing actin filaments around WPBs before fusion, dependent on zyxin and an interaction with the actin crosslinker α-actinin. Our findings identify zyxin as a physiological regulator of endothelial exocytosis through reorganizing local actin network in the final stage of exocytosis.
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http://dx.doi.org/10.1038/ncomms14639 | DOI Listing |
Virchows Arch
December 2021
Department of Plastic Surgery, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine malignancy of the skin. The cell of origin of MCC is thus far unknown and proposed cells of origin include Merkel cells, pro-/pre- or pre-B cells, epithelial stem cells, and dermal stem cells. In this study, we aimed to shed further light on the possibility that a subset of MCC tumors arise from epithelial stem cells of the skin by examining the expression of hair follicle and epidermal stem cell markers in MCC and normal human skin.
View Article and Find Full Text PDFAm J Med Genet A
June 2021
The Folkhaelsan Department of Medical Genetics, The Folkhaelsan Institute of Genetics and the Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland.
J Transl Med
October 2020
Institute of Neurophysiology, Medical Faculty Mannheim, University Heidelberg, Heidelberg, Germany.
J Eur Acad Dermatol Venereol
February 2019
Department of Dermatology, Allergology and Venereology, Helsinki University Central Hospital, Helsinki, Finland.
Transplantation
January 2016
1 Transplantation Laboratory, University of Helsinki, Helsinki, Finland. 2 Department of surgery, Oulu University Central Hospital, Oulu, Finland. 3 Transplantation and Liver Surgery Unit, Helsinki University Central Hospital, Helsinki, Finland. 4 Division of Nephrology, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland.
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