A new role for PTEN in regulating transient receptor potential canonical channel 6-mediated Ca2+ entry, endothelial permeability, and angiogenesis.
Phosphatase and tensin homologue (PTEN) is a dual lipid-protein phosphatase that catalyzes the conversion of phosphoinositol 3,4,5-triphosphate to phosphoinositol 4,5-bisphosphate and thereby inhibits PI3K-Akt-dependent cell proliferation, migration, and tumor vascularization. We have uncovered a previously unrecognized role for PTEN in regulating Ca(2+) entry through transient receptor potential canonical channel 6 (TRPC6) that does not require PTEN phosphatase activity. We show that PTEN tail-domain residues 394-403 permit PTEN to associate with TRPC6. The inflammatory mediator thrombin promotes this association. Deletion of PTEN residues 394-403 prevents TRPC6 cell surface expression and Ca(2+) entry. However, PTEN mutant, C124S, which lacks phosphatase activity, did not alter TRPC6 activity. Thrombin failed to increase endothelial monolayer permeability in the endothelial cells, transducing the Δ394-403 PTEN mutant. Paradoxically, we also show that thrombin failed to induce endothelial cell migration and tube formation in cells transducing the Δ394-403 PTEN mutant. Our results demonstrate that PTEN, through residues 394-403, serves as a scaffold for TRPC6, enabling cell surface expression of the channel. Ca(2+) entry through TRPC6 induces an increase in endothelial permeability and directly promotes angiogenesis. Thus, PTEN is indicated to play a role beyond suppressing PI3K signaling.
Kini
Vidisha
V
From the Department of Pharmacology and Center for Lung and Vascular Biology, College of Medicine, University of Illinois, Chicago, Illinois 60612.
Chavez
Alejandra
A
From the Department of Pharmacology and Center for Lung and Vascular Biology, College of Medicine, University of Illinois, Chicago, Illinois 60612.
Mehta
Dolly
D
From the Department of Pharmacology and Center for Lung and Vascular Biology, College of Medicine, University of Illinois, Chicago, Illinois 60612. Electronic address: dmehta@uic.edu.
D000595:Amino Acid Sequence; D002118:Calcium / Q000378:metabolism*; D002199:Capillary Permeability / Q000187:drug effects / Q000502:physiology*; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006490:Hemostatics / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism / Q000494:pharmacology; D007295:Inositol Phosphates / Q000235:genetics / Q000378:metabolism; D020125:Mutation, Missense; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000502:physiology*; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*; D000074287:TRPC6 Cation Channel; D013917:Thrombin / Q000378:metabolism / Q000494:pharmacology
D006490:Hemostatics; D018836:Inflammation Mediators; D007295:Inositol Phosphates; D050052:TRPC Cation Channels; D000074287:TRPC6 Cation Channel; C117032:TRPC6 protein, human; C118500:inositol 3,4,5-trisphosphate; C066454:inositol 4,5-bisphosphate; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; D013917:Thrombin; D002118:Calcium