Search

Your search keyword '"Zippel, R."' showing total 7 results
Start Over Author "Zippel, R." Journal experimental cell research
7 results on '"Zippel, R."'

5. The Ras Guanine Nucleotide Exchange Factor CDC25Mm Is Present at the Synaptic Junction

Author

Paola Branduardi, Emmapaola Sturani, Renata Zippel, Suzanne Denis-Donini, Adele Abbondio, Enzo Martegani, Cristina Ferrari, Marco Vanoni, Sturani, E, Abbondio, A, Branduardi, P, Ferrari, C, Zippel, R, Martegani, E, Vanoni, M, and Denis Donini, S

Subjects
Immunoblotting, CDC25Mm, Ras Guanine Nucleotide Exchange Factor, Synaptic Junction, Cell Cycle Proteins, Biology, Cell Fractionation, Synaptic vesicle, Nucleotide exchange factor, Mice, Ras-GRF1, GTP-Binding Proteins, Postsynaptic potential, Ca2+/calmodulin-dependent protein kinase, Phosphoprotein Phosphatases, Animals, Phosphorylation, ras-GRF1, Brain, Cell Biology, Immunohistochemistry, Cell biology, Calcium-Calmodulin-Dependent Protein Kinases, Synapses, Synaptic Vesicles, Guanine nucleotide exchange factor, Signal transduction, Cell fractionation, Calcium-Calmodulin-Dependent Protein Kinase Type 2, Signal Transduction, Synaptosomes
Abstract

CDC25Mm, a mouse Ras-Guanine nucleotide exchange factor, is specifically expressed as a product of 140 kDa (p140) in the postnatal and adult brain. Immunohistochemical analysis indicates that it is present throughout the brain particularly concentrated in discrete punctate structures. Subcellular fractionation of the mouse brain shows that p140 is present in synaptosomes but not in highly purified synaptic vesicles. Moreover, isolated postsynaptic densities (PSDs) are largely enriched in CDC25Mm. This protein can be phosphorylated by calcium/calmodulin kinase II, the most abundant protein in PSDs. Altogether these results suggest that CDC25Mm is present at synaptic junctions and that it may be involved in synaptic signal transduction leading to Ras activation.

Published
1997
Full Text
View/download PDF

6. Calcium and calmodulin are essential for Ras-GRF1-mediated activation of the Ras pathway by lysophosphatidic acid.

Author

Zippel R, Balestrini M, Lomazzi M, and Sturani E

Subjects
3T3 Cells, Animals, COS Cells, Calcium physiology, Calmodulin physiology, Cell Line, Fibroblasts cytology, Fibroblasts metabolism, Humans, Mice, Mitogen-Activated Protein Kinase 3, Mitogen-Activated Protein Kinases metabolism, ras-GRF1 genetics, Calcium metabolism, Calcium Signaling, Calmodulin metabolism, Lysophospholipids metabolism, ras Proteins metabolism, ras-GRF1 metabolism
Abstract

The exchange factor Ras-GRF1, also called CDC25Mm, couples calcium signaling and G-protein-coupled receptors to Ras and downstream effectors. Here we show that when expressed in different cell lines Ras-GRF1 strongly enhances the level of active Ras (Ras-GTP) and the activity of mitogen-activated protein kinases (MAPK). Moreover, in NIH 3T3 fibroblasts it potentiates the effect of lysophosphatidic acid (LPA) on Ras protein and MAPK activity. Calmodulin and cytosolic free calcium are essential for Ras and MAPK activation induced by LPA and mediated by Ras-GRF1, as shown by the finding that BAPTA-AM, an intracellular calcium chelator, and calmodulin inhibitors completely abolished this effect. This report demonstrates the relevance of calmodulin in addition to calcium for the response of Ras-GRF1 to LPA., (Copyright 2000 Academic Press.)

Published
2000
Full Text
View/download PDF

7. Voltage-dependent calcium current in adherent mouse 3T3 fibroblasts.

Author

Peres A, Sturani E, and Zippel R

Subjects
Action Potentials, Animals, Cadmium physiology, Cell Line, Magnesium physiology, Mice, Calcium Channels physiology, Cell Adhesion, Electrophysiology, Fibroblasts physiology
Abstract

Whole-cell recording was performed on adherent mouse Swiss 3T3 fibroblasts. Depolarizations from a holding potential of -100 mV gave rise to a transient inward current. The voltage dependence, kinetic properties, and ionic selectivity of this current are identical to those described in the same cells kept in suspension after detachment from the culture dish [A. Pandiella, A. Malgaroli, J. Meldolesi, and L.M. Vicentini (1987) Exp. Cell. Res. 170, 175-185; W.H. Moolenaar, L.G.J. Tertoolen, and S.W. de Laat (1984) J. Biol. Chem. 259, 8066-8069].

Published
1989
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results