title: Lateral diffusion of inositol 1,4,5-trisphosphate receptor type 1 in Purkinje cells is regulated by calcium and actin filaments.
abstract: Inositol 1,4,5-trisphosphate receptor type 1 (IP(3) R1) is an intracellular Ca(2+) release channel that plays crucial roles in the functions of Purkinje cells. The dynamics of IP(3) R1 on the endoplasmic reticulum membrane and the distribution of IP(3) R1 in neurons are thought to be important for the spatial regulation of Ca(2+) release. In this study, we analyzed the lateral diffusion of IP(3) R1 in Purkinje cells in cerebellar slice cultures using fluorescence recovery after photobleaching. In the dendrites of Purkinje cells, IP(3) R1 showed lateral diffusion with an effective diffusion constant of approximately 0.30 μm(2) /s, and the diffusion of IP(3) R1 was negatively regulated by actin filaments. We found that actin filaments were also involved in the regulation of IP(3) R1 diffusion in the spine of Purkinje cells. Glutamate or quisqualic acid stimulation, which activates glutamate receptors and leads to a Ca(2+) transient in Purkinje cells, decreased the diffusion of IP(3) R1 and increased the density of actin in spines. These findings indicate that the neuronal activity-dependent augmentation of actin contributes to the stabilization of IP(3) R1 in spines.
authors.affiliation: Laboratory for Developmental Neurobiology, Brain Science Institute RIKEN, Wako, Saitama, Japan.
authors.forename: Kazumi
authors.initials: K
authors.lastname: Fukatsu
authors.forename: Hiroko
authors.initials: H
authors.lastname: Bannai
authors.forename: Takafumi
authors.initials: T
authors.lastname: Inoue
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Mikoshiba
mesh_terms: D008841:Actin Cytoskeleton / Q000502:physiology*; D000199:Actins / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000502:physiology*; D003712:Dendrites / Q000187:drug effects / Q000378:metabolism*; D049229:Dendritic Spines / Q000187:drug effects / Q000378:metabolism; D004058:Diffusion; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D036681:Fluorescence Recovery After Photobleaching; D018698:Glutamic Acid / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000235:genetics; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D011689:Purkinje Cells / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D016318:Quisqualic Acid / Q000494:pharmacology; D017470:Receptors, Glutamate / Q000502:physiology; D046509:Tissue Culture Techniques
chemical_list: D000199:Actins; D018690:Excitatory Amino Acid Agonists; D053496:Inositol 1,4,5-Trisphosphate Receptors; D017470:Receptors, Glutamate; D049452:Green Fluorescent Proteins; D018698:Glutamic Acid; D016318:Quisqualic Acid; D002118:Calcium