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Literature summary for 3.6.5.2 extracted from
- Rap1 GTPases: an emerging role in the cardiovasculature (2011), Life Sci., 88, 645-652.
Activating Compound
| Activating Compound | Comment | Organism | Structure |
|---|---|---|---|
| C3G guanine nucleotide exchange factor | - |
Homo sapiens | |
| Calcium | - |
Mus musculus |  |
| CalDAG-GEF | a guanine nucleotide exchange factor | Homo sapiens | |
| cAMP | - |
Mus musculus | |
| cAMP | - |
Homo sapiens | |
| diacylglycerol | - |
Mus musculus | |
| diacylglycerol | - |
Homo sapiens | |
| forskolin | the adenylyl cyclase activator strongly and specifically activates Rap1 in microvascular smooth muscle cells | Homo sapiens | |
| PDZ-GEF1 | a guanine nucleotide exchange factor | Homo sapiens | |
| PDZ-GEF2 | a guanine nucleotide exchange factor | Homo sapiens | |
| PLCepsilon | a guanine nucleotide exchange factor | Homo sapiens | |
| RasGRP2 | a guanine nucleotide exchange factor | Homo sapiens |
Cloned(Commentary)
| Cloned (Comment) | Organism |
|---|---|
| genes rap1a and rap1b, genetic models | Mus musculus |
Protein Variants
| Protein Variants | Comment | Organism |
|---|---|---|
| additional information | overexpressing activated Rap 1a in dermal microvascular endothelial cells | Homo sapiens |
Inhibitors
| Inhibitors | Comment | Organism | Structure |
|---|---|---|---|
| Rap1Gap | the GTPase activating protein catalyzes the hydrolysis of GTP by its asparagine side chain rendering Rap1 inactive | Homo sapiens |
Metals/Ions
| Metals/Ions | Comment | Organism | Structure |
|---|---|---|---|
| Ca2+ | activates | Homo sapiens | |
Natural Substrates/ Products (Substrates)
| Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| GTP + H2O | Mus musculus | - |
GDP + phosphate | - |
? | |
| GTP + H2O | Homo sapiens | - |
GDP + phosphate | - |
? | |
Organism
| Organism | UniProt | Comment | Textmining |
|---|---|---|---|
| Homo sapiens | - |
two closely related isoforms, Rap1A and Rap1B encoded by genes rap1a and rap1b | - |
| Mus musculus | - |
two closely related isoforms, Rap1A and Rap1B | - |
Source Tissue
| Source Tissue | Comment | Organism | Textmining |
|---|---|---|---|
| B-lymphocyte | Rap1b is more highly expressed in B cells than Rap1a | Mus musculus | - |
| blood platelet | high expression of Rap1b | Mus musculus | - |
| cardiac myocyte | - |
Mus musculus | - |
| cardiac myocyte | - |
Homo sapiens | - |
| endothelial cell | - |
Mus musculus | - |
| endothelial cell | - |
Homo sapiens | - |
| heart | - |
Mus musculus | - |
| hematopoietic cell | - |
Mus musculus | - |
| hematopoietic cell | - |
Homo sapiens | - |
| myocardium | - |
Mus musculus | - |
| myocardium | - |
Homo sapiens | - |
| neutrophil | bone marrow-derived, high expression of Rap1a | Mus musculus | - |
| smooth muscle cell | - |
Mus musculus | - |
| smooth muscle cell | microvascular | Homo sapiens | - |
Substrates and Products (Substrate)
| Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| GTP + H2O | - |
Mus musculus | GDP + phosphate | - |
? | |
| GTP + H2O | - |
Homo sapiens | GDP + phosphate | - |
? | |
Synonyms
| Synonyms | Comment | Organism |
|---|---|---|
| monomeric G protein | - |
Mus musculus |
| monomeric G protein | - |
Homo sapiens |
| RAP | - |
Mus musculus |
| RAP | - |
Homo sapiens |
| Rap GTPase | - |
Mus musculus |
| Rap GTPase | - |
Homo sapiens |
| Ras related GTPase Rap | - |
Mus musculus |
| Ras related GTPase Rap | - |
Homo sapiens |
General Information
| General Information | Comment | Organism |
|---|---|---|
| evolution | Rap GTPase is a member of the Ras superfamily | Mus musculus |
| evolution | Rap GTPase is a member of the Ras superfamily | Homo sapiens |
| malfunction | in cultured human microvascular endothelial cells, knockdown of either Rap1a or 1b appears to diminish adhesion to the extracellular matrix and impair cell migration, and also increases permeability. Loss of Rap1a or 1b unexpectedly blocked angiogenesis by abolishing the angiogenic response to FGF2 or to VEGF, leading to an inability for these cells to form tubular structures. Ablation of either isoforms leads to decrease in FGF-2 mediated ERK, p38 and Rac activation which are all important angiogenesis signaling molecules. Overexpressing activated Rap 1a in dermal microvascular endothelial cells show defective angiogenesis through regulation of thrombospondin-1 | Homo sapiens |
| malfunction | the loss of Rap1b leads to deficiencies both in B cell migration and in adhesion. Platelets from Rap1b null mice exhibit defective aggregation in response to integrin stimulation. These mice exhibit protection from arterial thrombosis and provide an independent role for this Rap1 isoform | Mus musculus |
| additional information | activation of Rap1 by Epac1 leads to increased integrin activity and adhesion of endothelial progenitor cells, CD34+ hematopoietic progenitor cells and mesenchylmal stem cells, which show increased homing and neovascularization capabilities | Mus musculus |
| physiological function | Rap1A and Rap1B have differing roles in the cardiovasculature. Activation of Rap1a and 1b in various cell types of the cardiovasculature lead to alterations in cell attachment, migration and cell junction formation. Rap1b is necessary for proper development, homing and T cell dependant immunity. Rap1b protein regulates the SERCA 3b-associated Ca2+ pool through its cAMP-dependent phosphorylation, and therefore plays a role in the transition between platelet activation and inhibition. Whereas Rap1a and 1b appear to be key regulators in differing cell types of the blood, neutrophils and platelets, both appear to contribute to the normal function of endothelial cells and to angiogenesis. In smooth muscle cells, Rap1 may elicit a protective response to maintain vessel wall integrity in response to cellular stress | Mus musculus |
| physiological function | the GTP-bound Rap mediates signaling by associating with, and activating effector proteins. Whereas Rap1a and 1b appear to be key regulators in differing cell types of the blood, neutrophils and platelets, both appear to contribute to the normal function of endothelial cells and to angiogenesis. Endothelial cell junctional proteins are involved in regulating vascular permeability. This dynamic regulation is regulated in part by Rap1 in response to cAMP activation through Epac1. In cultured human umbilical vein endothelial cells activation of Epac1-Rap1 by cAMP enhances endothelial barrier function by altering actin cytoskeleton organization, activating microtubule growth and results in a redistribution of adherens junctional proteins involving MAGI-1 protein. Rap1a and b are involved in the activation of beta1-integrins in endothelial cells and play a key role in integrin dependent angiogenic functions such as sprouting, tube formation, migration and adhesion. In smooth muscle cells, Rap1 may elicit a protective response to maintain vessel wall integrity in response to cellular stress | Homo sapiens |
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