Uehara Kiyoko, Uehara Akira
Department of Cell Biology, Fukuoka University School of Medicine, Jonan-ku, Fukuoka, 814-0180, Japan.
Department of Physiology, Fukuoka University School of Medicine, Jonan-ku, Fukuoka, 814-0180, Japan.
Cell Tissue Res. 2016 Jun;364(3):611-622. doi: 10.1007/s00441-015-2350-1. Epub 2016 Feb 5.
The splenic sinus endothelium adhering via adherens junctions and tight junctions regulates the passage of blood cells through the splenic cord. Focal adhesion kinase (FAK) regulates the focal adhesion complex in the basal part of endothelial cells and is an integrated component of cell-cell adhesion, depending on its phosphorylation status. The objectives of this study are to assess the localization of FAK phosphorylated at tyrosine residues and the related proteins of integrin β5, talin, paxillin, p130Cas, vinculin, RhoA, Rac1, Rac2, Cdc42 and VE-cadherin, in the sinus endothelial cells of rat spleen and to examine the roles of FAK in regulating endothelial adhesion and the passage of blood cells. Immunofluorescence microscopy of tissue cryosections revealed that FAK was localized in the entire circumference of sinus endothelial cells and FAK phosphorylated at Try397 residue (pFAKy397) and pFAKy576 were precisely localized in the adherens junctions of the endothelial cells, whereas pFAKy925 was localized in the basal part of the endothelial cells. Paxillin and vinculin were prominently localized in the basal part of the endothelial cells. Integrin β5, talin and p130Cas were colocalized with FAK in the entire circumference of sinus endothelial cells. RhoA, Rac2 and Cdc42 were localized in the entire circumference of sinus endothelial cells close to FAK, stress fibers and cortical actin filaments. Immunogold electron microscopy revealed that pFAKy397 and pFAKy576 were colocalized with VE-cadherin, RhoA, Rac2 and Cdc42 in the adherens junctions of the endothelial cells. Possible functional roles of FAK in splenic sinus endothelial cells are also discussed.
通过黏附连接和紧密连接黏附的脾窦内皮调节血细胞通过脾索的通道。黏着斑激酶（FAK）调节内皮细胞基部的黏着斑复合体，并且根据其磷酸化状态，是细胞间黏附的一个整合成分。本研究的目的是评估在大鼠脾脏窦内皮细胞中酪氨酸残基磷酸化的FAK以及整合素β5、踝蛋白、桩蛋白、p130Cas、纽蛋白、RhoA、Rac1、Rac2、Cdc42和血管内皮钙黏蛋白相关蛋白的定位，并研究FAK在调节内皮黏附和血细胞通过中的作用。组织冰冻切片的免疫荧光显微镜检查显示，FAK定位于窦内皮细胞的整个周边，在Try397残基（pFAKy397）和pFAKy576处磷酸化的FAK精确地定位于内皮细胞的黏附连接处，而pFAKy925定位于内皮细胞的基部。桩蛋白和纽蛋白显著定位于内皮细胞的基部。整合素β5、踝蛋白和p130Cas与FAK在窦内皮细胞的整个周边共定位。RhoA、Rac2和Cdc42定位于靠近FAK、应力纤维和皮质肌动蛋白丝的窦内皮细胞的整个周边。免疫金电子显微镜显示，pFAKy397和pFAKy576与血管内皮钙黏蛋白、RhoA、Rac2和Cdc42在内皮细胞的黏附连接处共定位。还讨论了FAK在脾窦内皮细胞中可能的功能作用。
