PUBLICATION
A mechanism of Rap1-induced stabilization of endothelial cell--cell junctions
- Authors
- Liu, J.J., Stockton, R.A., Gingras, A.R., Ablooglu, A.J., Han, J., Bobkov, A.A., Ginsberg, M.H.
- ID
- ZDB-PUB-190719-5
- Date
- 2011
- Source
- Molecular biology of the cell 22: 2509-19 (Journal)
- Registered Authors
- Ablooglu, Ararat
- Keywords
- none
- MeSH Terms
-
- Cardiovascular System/growth & development
- Cardiovascular System/metabolism
- Microtubules/genetics
- Microtubules/metabolism
- Gene Expression
- Zebrafish/genetics
- Zebrafish/growth & development*
- Zebrafish/metabolism
- KRIT1 Protein
- Microtubule-Associated Proteins/chemistry
- Microtubule-Associated Proteins/genetics
- Microtubule-Associated Proteins/metabolism*
- Protein Structure, Tertiary
- Endothelial Cells/metabolism
- Endothelial Cells/physiology
- Umbilical Veins/cytology
- Zebrafish Proteins/chemistry
- Zebrafish Proteins/genetics
- Zebrafish Proteins/metabolism*
- Zebrafish Proteins/physiology
- Genetic Vectors
- RNA, Small Interfering
- Animals
- Signal Transduction
- Humans
- Monomeric GTP-Binding Proteins/chemistry
- Monomeric GTP-Binding Proteins/genetics
- Monomeric GTP-Binding Proteins/metabolism*
- Intercellular Junctions/genetics*
- Intercellular Junctions/metabolism
- Proto-Oncogene Proteins/chemistry
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism*
- Muscle Proteins/genetics
- Muscle Proteins/metabolism*
- Muscle Proteins/physiology
- HEK293 Cells
- rap1 GTP-Binding Proteins/chemistry
- rap1 GTP-Binding Proteins/genetics
- rap1 GTP-Binding Proteins/metabolism*
- Structure-Activity Relationship
- Protein Conformation
- PubMed
- 21633110 Full text @ Mol. Biol. Cell
Citation
Liu, J.J., Stockton, R.A., Gingras, A.R., Ablooglu, A.J., Han, J., Bobkov, A.A., Ginsberg, M.H. (2011) A mechanism of Rap1-induced stabilization of endothelial cell--cell junctions. Molecular biology of the cell. 22:2509-19.
Abstract
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.
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