Among 335 plasma membrane proteins identified in the present study, several VEC membrane marker proteins were included. ICAM-2 is a type I transmembrane glycoprotein that is constitutively expressed www.selleckchem.com/products/sbe-b-cd.html in VECs [17] and mediates adhesive interactions between cells involved in antigen-specific immune response, natural killer (NK)-cell-mediated clearance, lymphocyte recirculation, and other cellular interactions. Integrin

alpha-1 is known to be expressed in both leukocytes and endothelium and to participate in cell adhesion as well as cell-surface-mediated signaling, involving leukocyte adhesion to VEC, migration into the subendothelial matrix, and neural migration [18]. Von Willebrand factor (vWf) was also identified in this study, which is well known to be involved in hemostasis and is also a blood type ABO antigen-carrying protein. It exists as a multimeric plasma glycoprotein and a membrane-bound protein in VECs and megakaryocytes. Immunofluorescence microscopy demonstrated its localization in VECs of the

human kidney [19]. Eight novel proteins, not previously reported in kidney VEC, were identified as plasma membrane proteins. One of them was Dll3, which has been reported to participate in the Notch signaling pathway and to RXDX-101 control cell fate determination in multicellular animals [20, 21]. Dll3 binds to Deltex 1 via its unique N-terminus [22]. Deltex 1 RG7420 ic50 serves as an important signaling transcriptional regulator downstream of Notch receptor [23]. Notch receptor is a critical downstream effector of arteriogenic and angiogenic responses to vascular endothelial growth factor (VEGF) [24]. Our immunohistochemical and immunofluorescence results provide

the first evidence that Dll3 is localized uniquely to VECs in kidney, although the precise role of Deltex/Notch signaling in governing endothelial cell Tau-protein kinase behavior remains unclear. In kidney, Dll3, a newly identified ligand responsible for activation of Notch receptor, was uniquely expressed in arterial endothelium, indicating that Dll3 may potentially be a new VEC marker protein and suggesting a potential role of Dll3 in modulating arterial development (arteriogenesis). Further studies are needed to evaluate the roles of Dll3 in kidney VECs and to gain further insight into the critical role of Notch signaling in arteriogenesis and angiogenesis. Beyond single-protein functional studies in kidney VECs, our study opens the door to understanding the biologic roles of kidney VEC plasma membrane proteins and provides important details about biologic processes, molecular functions, and molecular relationships within the proteome. Moreover, previous proteomic analyses identified approximately 60 proteins in cultured endothelial cells, although few proteins were VEC marker proteins [3, 25].