The Ras Guanine nucleotide Exchange Factor CDC25Mm is present at the synaptic junction.
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.
Sturani
E
E
Department of General Physiology and Biochemistry, Department of Biology, University of Milan, Via Celoria 26, Milano, 20133, Italia.
Abbondio
A
A
Branduardi
P
P
Ferrari
C
C
Zippel
R
R
Martegani
E
E
Vanoni
M
M
Denis-Donini
S
S
D000818:Animals; D001921:Brain / Q000166:cytology* / Q000502:physiology; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000032:analysis* / Q000378:metabolism; D002458:Cell Fractionation; D019204:GTP-Binding Proteins / Q000032:analysis*; D015151:Immunoblotting; D007150:Immunohistochemistry; D051379:Mice; D010749:Phosphoprotein Phosphatases / Q000032:analysis* / Q000378:metabolism; D010766:Phosphorylation; D015398:Signal Transduction; D013569:Synapses / Q000502:physiology / Q000648:ultrastructure*; D013572:Synaptic Vesicles / Q000648:ultrastructure; D013574:Synaptosomes / Q000648:ultrastructure; D020666:ras-GRF1
D018797:Cell Cycle Proteins; D020666:ras-GRF1; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D010749:Phosphoprotein Phosphatases; D019204:GTP-Binding Proteins