scholarly journals KRIT-1/CCM1 is a Rap1 effector that regulates endothelial cell–cell junctions

2007 ◽  
Vol 179 (2) ◽  
pp. 247-254 ◽  
Author(s):  
Angela Glading ◽  
Jaewon Han ◽  
Rebecca A. Stockton ◽  
Mark H. Ginsberg
Keyword(s):  
Endothelial Cell ◽  
Protein Function ◽  
Cell Junctions ◽  
Stress Fibers ◽  
Ferm Domain ◽  
Endothelial Junctions ◽  
Guanosine Triphosphatase ◽  
Interfering Rna ◽  
Junction Proteins ◽  
Cell Cell

Cerebral cavernous malformation (CCM), a disease associated with defective endothelial junctions, result from autosomal dominant CCM1 mutations that cause loss of KRIT-1 protein function, though how the loss of KRIT-1 leads to CCM is obscure. KRIT-1 binds to Rap1, a guanosine triphosphatase that maintains the integrity of endothelial junctions. Here, we report that KRIT-1 protein is expressed in cultured arterial and venous endothelial cells and is present in cell–cell junctions. KRIT-1 colocalized and was physically associated with junctional proteins via its band 4.1/ezrin/radixin/moesin (FERM) domain. Rap1 activity regulated the junctional localization of KRIT-1 and its physical association with junction proteins. However, the association of the isolated KRIT-1 FERM domain was independent of Rap1. Small interfering RNA–mediated depletion of KRIT-1 blocked the ability of Rap1 to stabilize endothelial junctions associated with increased actin stress fibers. Thus, Rap1 increases KRIT-1 targeting to endothelial cell–cell junctions where it suppresses stress fibers and stabilizes junctional integrity.

scholarly journals Golgi-associated cPLA2α Regulates Endothelial Cell–Cell Junction Integrity by Controlling the Trafficking of Transmembrane Junction Proteins

2009 ◽  
Vol 20 (19) ◽  
pp. 4225-4234 ◽  
Author(s):  
Elsa Regan-Klapisz ◽  
Vincent Krouwer ◽  
Miriam Langelaar-Makkinje ◽  
Laxman Nallan ◽  
Michael Gelb ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Intracellular Trafficking ◽  
Adherens Junction ◽  
Cell Junctions ◽  
Cell Junction ◽  
Tight Junction Formation ◽  
Junction Formation ◽  
Junction Proteins ◽  
Cell Cell

In endothelial cells specifically, cPLA2α translocates from the cytoplasm to the Golgi complex in response to cell confluence. Considering the link between confluence and cell–cell junction formation, and the emerging role of cPLA2α in intracellular trafficking, we tested whether Golgi-associated cPLA2α is involved in the trafficking of junction proteins. Here, we show that the redistribution of cPLA2α from the cytoplasm to the Golgi correlates with adherens junction maturation and occurs before tight junction formation. Disruption of adherens junctions using a blocking anti-VE-cadherin antibody reverses the association of cPLA2α with the Golgi. Silencing of cPLA2α and inhibition of cPLA2α enzymatic activity using various inhibitors result in the diminished presence of the transmembrane junction proteins VE-cadherin, occludin, and claudin-5 at cell–cell contacts, and in their accumulation at the Golgi. Altogether, our data support the idea that VE-cadherin triggers the relocation of cPLA2α to the Golgi and that in turn, Golgi-associated cPLA2α regulates the transport of transmembrane junction proteins through or from the Golgi, thereby controlling the integrity of endothelial cell–cell junctions.

scholarly journals Rap1 potentiates endothelial cell junctions by spatially controlling myosin II activity and actin organization

2013 ◽  
Vol 202 (6) ◽  
pp. 901-916 ◽  
Author(s):  
Koji Ando ◽  
Shigetomo Fukuhara ◽  
Takahiro Moriya ◽  
Yutaro Obara ◽  
Norimichi Nakahata ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Radial Stress ◽  
Myosin Ii ◽  
Small Gtpase ◽  
Cell Junctions ◽  
Stress Fibers ◽  
Dynamic Regulation ◽  
Actin Organization ◽  
Muscle Myosin ◽  
Cell Cell

Reorganization of the actin cytoskeleton is responsible for dynamic regulation of endothelial cell (EC) barrier function. Circumferential actin bundles (CAB) promote formation of linear adherens junctions (AJs) and tightening of EC junctions, whereas formation of radial stress fibers (RSF) connected to punctate AJs occurs during junction remodeling. The small GTPase Rap1 induces CAB formation to potentiate EC junctions; however, the mechanism underlying Rap1-induced CAB formation remains unknown. Here, we show that myotonic dystrophy kinase–related CDC42-binding kinase (MRCK)-mediated activation of non-muscle myosin II (NM-II) at cell–cell contacts is essential for Rap1-induced CAB formation. Our data suggest that Rap1 induces FGD5-dependent Cdc42 activation at cell–cell junctions to locally activate the NM-II through MRCK, thereby inducing CAB formation. We further reveal that Rap1 suppresses the NM-II activity stimulated by the Rho–ROCK pathway, leading to dissolution of RSF. These findings imply that Rap1 potentiates EC junctions by spatially controlling NM-II activity through activation of the Cdc42–MRCK pathway and suppression of the Rho–ROCK pathway.

scholarly journals Angiomotin Regulates Endothelial Cell-Cell Junctions and Cell Motility

2005 ◽  
Vol 280 (41) ◽  
pp. 34859-34869 ◽  
Author(s):  
Anders Bratt ◽  
Olivier Birot ◽  
Indranil Sinha ◽  
Niina Veitonmäki ◽  
Karin Aase ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Cell Motility ◽  
Cell Junctions ◽  
Cell Cell

scholarly journals Brain Endothelial Cell-Cell Junctions: How to “Open” the Blood Brain Barrier

2008 ◽  
Vol 6 (3) ◽  
pp. 179-192 ◽  
Author(s):  
Svetlana Stamatovic ◽  
Richard Keep ◽  
Anuska Andjelkovic
Keyword(s):  
Endothelial Cell ◽  
Blood Brain Barrier ◽  
Cell Junctions ◽  
Brain Barrier ◽  
Brain Endothelial Cell ◽  
Blood Brain ◽  
Cell Cell

scholarly journals A mechanism of Rap1-induced stabilization of endothelial cell–cell junctions

2011 ◽  
Vol 22 (14) ◽  
pp. 2509-2519 ◽  
Author(s):  
Jian J. Liu ◽  
Rebecca A. Stockton ◽  
Alexandre R. Gingras ◽  
Ararat J. Ablooglu ◽  
Jaewon Han ◽  
...  
Keyword(s):  
Endothelial Cell ◽  
Small Gtpases ◽  
Cell Junctions ◽  
Physical Interaction ◽  
Dependent Manner ◽  
Cardiovascular Development ◽  
Cavernous Malformations ◽  
Cell Cell

Activation of Rap1 small GTPases stabilizes cell–cell junctions, and this activity requires Krev Interaction Trapped gene 1 (KRIT1). Loss of KRIT1 disrupts cardiovascular development and causes autosomal dominant familial cerebral cavernous malformations. Here we report that native KRIT1 protein binds the effector loop of Rap1A but not H-Ras in a GTP-dependent manner, establishing that it is an authentic Rap1-specific effector. By modeling the KRIT1–Rap1 interface we designed a well-folded KRIT1 mutant that exhibited a ∼40-fold-reduced affinity for Rap1A and maintained other KRIT1-binding functions. Direct binding of KRIT1 to Rap1 stabilized endothelial cell–cell junctions in vitro and was required for cardiovascular development in vivo. Mechanistically, Rap1 binding released KRIT1 from microtubules, enabling it to locate to cell–cell junctions, where it suppressed Rho kinase signaling and stabilized the junctions. These studies establish that the direct physical interaction of Rap1 with KRIT1 enables the translocation of microtubule-sequestered KRIT1 to junctions, thereby supporting junctional integrity and cardiovascular development.

scholarly journals Involvement of Actinin-4 in the Recruitment of JRAB/MICAL-L2 to Cell-Cell Junctions and the Formation of Functional Tight Junctions

2008 ◽  
Vol 28 (10) ◽  
pp. 3324-3335 ◽  
Author(s):  
Hiroyoshi Nakatsuji ◽  
Noriyuki Nishimura ◽  
Rie Yamamura ◽  
Hiro-omi Kanayama ◽  
Takuya Sasaki
Keyword(s):  
Tight Junctions ◽  
Binding Protein ◽  
Cell Junctions ◽  
Actin Binding ◽  
Deletion Mutants ◽  
Yeast Two Hybrid ◽  
Yeast Two Hybrid System ◽  
Interfering Rna ◽  
Two Hybrid ◽  
Cell Cell

ABSTRACT Tight junctions (TJs) are cell-cell adhesive structures that undergo continuous remodeling. We previously demonstrated that Rab13 and a junctional Rab13-binding protein (JRAB)/molecule interacting with CasL-like 2 (MICAL-L2) localized at TJs and mediated the endocytic recycling of the integral TJ protein occludin and the formation of functional TJs. Here, we investigated how JRAB/MICAL-L2 was targeted to TJs. Using a series of deletion mutants, we found the plasma membrane (PM)-targeting domain within JRAB/MICAL-L2. We then identified actinin-4, which was originally isolated as an actin-binding protein associated with cell motility and cancer invasion/metastasis, as a binding protein for the PM-targeting domain of JRAB/MICAL-L2, using a yeast two-hybrid system. Actinin-4 was colocalized with JRAB/MICAL-L2 at cell-cell junctions and linked JRAB/MICAL-L2 to F-actin. Although actinin-4 bound to JRAB/MICAL-L2 without Rab13, the actinin-4-JRAB/MICAL-L2 interaction was enhanced by Rab13 activation. Depletion of actinin-4 by using small interfering RNA inhibited the recruitment of occludin to TJs during the Ca2+ switch. During the epithelial polarization after replating, JRAB/MICAL-L2 was recruited from the cytosol to cell-cell junctions. This JRAB/MICAL-L2 recruitment as well as the formation of functional TJs was delayed in actinin-4-depleted cells. These results indicate that actinin-4 is involved in recruiting JRAB/MICAL-L2 to cell-cell junctions and forming functional TJs.

scholarly journals PKM2 regulates endothelial cell junction dynamics and angiogenesis via ATP production

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jesús Gómez-Escudero ◽  
Cristina Clemente ◽  
Diego García-Weber ◽  
Rebeca Acín-Pérez ◽  
Jaime Millán ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Inflammatory Disease ◽  
Chronic Inflammatory Disease ◽  
Cell Junctions ◽  
Cell Junction ◽  
Collective Migration ◽  
Sprouting Angiogenesis ◽  
Cell Cell

Abstract Angiogenesis, the formation of new blood vessels from pre-existing ones, occurs in pathophysiological contexts such as wound healing, cancer, and chronic inflammatory disease. During sprouting angiogenesis, endothelial tip and stalk cells coordinately remodel their cell-cell junctions to allow collective migration and extension of the sprout while maintaining barrier integrity. All these processes require energy, and the predominant ATP generation route in endothelial cells is glycolysis. However, it remains unclear how ATP reaches the plasma membrane and intercellular junctions. In this study, we demonstrate that the glycolytic enzyme pyruvate kinase 2 (PKM2) is required for sprouting angiogenesis in vitro and in vivo through the regulation of endothelial cell-junction dynamics and collective migration. We show that PKM2-silencing decreases ATP required for proper VE-cadherin internalization/traffic at endothelial cell-cell junctions. Our study provides fresh insight into the role of ATP subcellular compartmentalization in endothelial cells during angiogenesis. Since manipulation of EC glycolysis constitutes a potential therapeutic intervention route, particularly in tumors and chronic inflammatory disease, these findings may help to refine the targeting of endothelial glycolytic activity in disease.

scholarly journals Molecular and cellular properties of PECAM-1 (endoCAM/CD31): a novel vascular cell-cell adhesion molecule.

1991 ◽  
Vol 114 (5) ◽  
pp. 1059-1068 ◽  
Author(s):  
S M Albelda ◽  
W A Muller ◽  
C A Buck ◽  
P J Newman
Keyword(s):  
Cell Adhesion ◽  
Endothelial Cell ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Intercellular Junctions ◽  
Cell Junctions ◽  
Immunoglobulin Gene ◽  
Vascular Cell ◽  
L Cells ◽  
Cell Cell

PECAM-1 is a 130-120-kD integral membrane glycoprotein found on the surface of platelets, at endothelial intercellular junctions in culture, and on cells of myeloid lineage. Previous studies have shown that it is a member of the immunoglobulin gene superfamily and that antibodies against the bovine form of this protein (endoCAM) can inhibit endothelial cell-cell interactions. These data suggest that PECAM-1 may function as a vascular cell adhesion molecule. The function of this molecule has been further evaluated by transfecting cells with a full-length PECAM-1 cDNA. Transfected COS-7, mouse 3T3 and L cells expressed a 130-120-kD glycoprotein on their cell surface that reacted with anti-PECAM-1 polyclonal and monoclonal antibodies. COS-7 and 3T3 cell transfectants formed cell-cell junctions that were highly enriched in PECAM-1, reminiscent of its distribution at endothelial cell-cell borders. In contrast, this protein remained diffusely distributed within the plasma membrane of PECAM-1 transfected cells that were in contact with mock transfectants. Mouse L cells stably transfected with PECAM-1 demonstrated calcium-dependent aggregation that was inhibited by anti-PECAM antibodies. These results demonstrate that PECAM-1 mediates cell-cell adhesion and support the idea that it may be involved in some of the interactive events taking place during thrombosis, wound healing, and angiogenesis.

Sign in / Sign up

Export Citation Format

Share Document