Journal Article

Actions of the protein kinase WNK1 on endothelial cells are differentially mediated by its substrate kinases OSR1 and SPAK

Perera, G. K. Sachith, Dbouk, Hashem A., Cobb, Melanie H., Brekken, Rolf A., Weil, Lauren M., Dellinger, Michael T., Pearson, Gray

2014

Overview

The with no lysine (K) (WNK) family of enzymes is best known for control of blood pressure through regulation of the function and membrane localization of ion cotransporters. In mice, global as well as endothelial-specific WNK1 gene disruption results in embryonic lethality due to angiogenic and cardiovascular defects. WNK1 ⁻/⁻ embryos can be rescued by endothelial-specific expression of a constitutively active form of the WNK1 substrate protein kinase OSR1 (oxidative stress responsive 1). Using human umbilical vein endothelial cells (HUVECs), we explored mechanisms underlying the requirement of WNK1–OSR1 signaling for vascular development. WNK1 is required for cord formation in HUVECs, but the actions of the two major WNK1 effectors, OSR1 and its close relative SPAK (STE20/SPS1-related proline-, alanine-rich kinase), are distinct. SPAK is important for endothelial cell proliferation, whereas OSR1 is required for HUVEC chemotaxis and invasion. We also identified the zinc-finger transcription factor Slug in WNK1-mediated control of endothelial functions. Our study identifies a separation of functions for the WNK1-activated protein kinases OSR1 and SPAK in mediating proliferation, invasion, and gene expression in endothelial cells and an unanticipated link between WNK1 and Slug that is important for angiogenesis. Significance With no lysine (K) (WNK)1, which is mutated in pseudohypoaldosteronism type II (PHAII) autosomal dominant hypertension, is a large, complex enzyme essential for development, blood pressure control, and many cellular functions. WNK1 signaling is largely mediated by two downstream protein kinases, OSR1 (oxidative stress responsive 1) and SPAK (STE20/SPS1-related proline-, alanine-rich kinase), sometimes considered redundant in terms of WNK1 function. This study characterizes an essential contribution of WNK1 in angiogenesis and presents a mechanism of clear bifurcation in WNK1-dependent functions between OSR1 and SPAK, with SPAK regulating WNK1 effects on proliferation and OSR1 mediating effects on invasion. Our work also identifies a previously unidentified link between WNK1 and the zinc-finger transcription factor Slug, with implications in cancer biology. This study also suggests potential mechanisms for cardiovascular defects associated with PHAII.

• Publisher: National Academy of Sciences,National Acad Sciences
• Subject: Angiogenesis / Animals / Biological Sciences / Blood pressure / Cell growth / Cell Proliferation - physiology / Cells / Embryos / Endothelial cells / Enzymes / Gene expression / Gene expression regulation / Gene Expression Regulation - physiology / Human umbilical vein endothelial cells / Human Umbilical Vein Endothelial Cells - cytology / Human Umbilical Vein Endothelial Cells - metabolism / Humans / hypertension / Intracellular Signaling Peptides and Proteins - genetics / Intracellular Signaling Peptides and Proteins - metabolism / Kinases / lysine / Membranes / Messenger RNA / Mice / Mice, Knockout / Minor Histocompatibility Antigens / neoplasms / Neovascularization, Physiologic - physiology / Oxidative stress / protein kinases / Protein-Serine-Threonine Kinases - genetics / Protein-Serine-Threonine Kinases - metabolism / Signal Transduction - physiology / Slugs / Small interfering RNA / Snail Family Transcription Factors / Sprouting / Transcription factors / Transcription Factors - genetics / Transcription Factors - metabolism / WNK Lysine-Deficient Protein Kinase 1