Cerebellar Defects in Ca2+/Calmodulin Kinase IV-Deficient Mice

• Published in: The Journal of neuroscience 2000-11, Vol.20 (22), p.107-RC107
• Main Authors: Ribar, Thomas J, Rodriguiz, Ramona M, Khiroug, Leonard, Wetsel, William C, Augustine, George J, Means, Anthony R
• Format: Article
• Language: English
• Subjects: Animals; Behavior, Animal; Blotting, Western; Calcium-Calmodulin-Dependent Protein Kinase Kinase; Calcium-Calmodulin-Dependent Protein Kinase Type 1; Calcium-Calmodulin-Dependent Protein Kinase Type 2; Calcium-Calmodulin-Dependent Protein Kinase Type 4; Calcium-Calmodulin-Dependent Protein Kinases - deficiency; Calcium-Calmodulin-Dependent Protein Kinases - genetics; Calcium-Calmodulin-Dependent Protein Kinases - metabolism; Cerebellar Diseases - enzymology; Cerebellar Diseases - genetics; Cerebellar Diseases - physiopathology; Cerebellum - enzymology; Cerebellum - pathology; Cerebellum - physiopathology; Cyclic AMP Response Element-Binding Protein - metabolism; Cyclic AMP Response Element-Binding Protein - pharmacokinetics; Cyclic AMP-Dependent Protein Kinases - metabolism; Electric Stimulation; Excitatory Postsynaptic Potentials - genetics; Heterozygote; Homozygote; In Vitro Techniques; Mice; Mice, Knockout; Phosphorylation; Protein-Serine-Threonine Kinases - metabolism; Purkinje Cells - enzymology; Purkinje Cells - pathology; Rapid Communication
• ISSN: 0270-6474; 1529-2401
• DOI: 10.1523/jneurosci.20-22-j0004.2000

The Ca(2+)/calmodulin-dependent protein kinase CaMKIV was first identified in the cerebellum and has been implicated in nuclear signaling events that control neuronal growth, differentiation, and plasticity. To understand the physiological importance of CaMKIV, we disrupted the mouse Camk4 gene. The CaMKIV null mice displayed locomotor defects consistent with altered cerebellar function. Although the overall cytoarchitecture of the cerebellum appeared normal in the Camk4(-/-) mice, we observed a significant reduction in the number of mature Purkinje neurons and reduced expression of the protein marker calbindin D28k within individual Purkinje neurons. Western immunoblot analyses of cerebellar extracts also established significant deficits in the phosphorylation of cAMP response element-binding protein at serine-133, a proposed target of CaMKIV. Additionally, the absence of CaMKIV markedly altered neurotransmission at excitatory synapses in Purkinje cells. Multiple innervation by climbing fibers and enhanced parallel fiber synaptic currents suggested an immature development of Purkinje cells in the Camk4(-/-) mice. Together, these findings demonstrate that CaMKIV plays key roles in the function and development of the cerebellum.