Chemical stimulation of synaptosomes modulates alpha -Ca2+/calmodulin-dependent protein kinase II mRNA association to polysomes.
The presence of specific mRNAs in dendrites and at synapses is well established, but a direct and reliable demonstration that they are associated with polysomes is still missing. To address this point we analyzed the polysomal association of the mRNAs for the alpha-subunit of Ca(2+)/calmodulin-dependent protein kinase II (alpha-CaMKII), for type 1 inositol 1,4,5-trisphosphate receptor (InsP3R1) and for the activity-regulated cytoskeleton-associated protein (Arc) in a synaptosomal preparation devoid of contaminating material from neuronal and glial perikarya. We show that a fraction of alpha-CaMKII, InsP3R1, and Arc mRNAs present in synaptosomes is indeed associated with polysomes. Moreover, we show that polysomal association of alpha-CaMKII mRNA, but not InsP3R1 and Arc mRNAs, increases with depolarization of the synaptosomal membrane. Finally, we show that the synthesis of alpha-CaMKII protein increases with stimulation. Dendritic mRNA recruitment onto polysomes in response to synaptic stimulation might represent one of the mechanisms underlying the processes of learning and memory.
Bagni
C
C
Dipartimento di Biologia, Università di Roma "Tor Vergata," 00133 Rome, Italy. bagni@uniroma2.it
Mannucci
L
L
Dotti
C G
CG
Amaldi
F
F
D000818:Animals; D001921:Brain / Q000648:ultrastructure; D015220:Calcium Channels / Q000378:metabolism; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000378:metabolism; D066298:In Vitro Techniques; D053496:Inositol 1,4,5-Trisphosphate Receptors; D051379:Mice; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D009419:Nerve Tissue Proteins / Q000378:metabolism; D011132:Polyribosomes / Q000201:enzymology / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D013268:Stimulation, Chemical; D013574:Synaptosomes / Q000201:enzymology / Q000378:metabolism*
D015220:Calcium Channels; D003598:Cytoskeletal Proteins; D053496:Inositol 1,4,5-Trisphosphate Receptors; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; C092069:activity regulated cytoskeletal-associated protein; D011189:Potassium Chloride; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C517671:Camk2a protein, mouse