Cyclin-dependent kinase 5 with phosphorylation of tyrosine 15 residue is enriched in striatal matrix compartment in adult mice.

Accumulating evidence suggests that the striosome-matrix systems have a tight link with motor and behavioral brain functions and their disorders. Cyclin-dependent kinase 5 (Cdk5) is a versatile protein kinase that plays a role in synaptic functions and cell survival in adult brain, and its kinase activity is stimulated by phosphorylation at tyrosine 15 residue (pY15). In this study, we used an immunohistochemical method to show differential localization of Cdk5-pY15 in the striatal compartments of adult mice, with a heightened density of Cdk5-pY15 labeling in the matrix relative to the striosomes. Our findings indicate that Cdk5-pY15 can be a new marker for the striatal matrix compartment, and suggest a possible involvement of Cdk5-mediated signaling in compartment-specific neurotransmission and disease pathology in the striatum.

Identification and localization of a neuron-specific isoform of TAF1 in rat brain: implications for neuropathology of DYT3 dystonia.

The neuron-specific isoform of the TAF1 gene (N-TAF1) is thought to be involved in the pathogenesis of DYT3 dystonia, which leads to progressive neurodegeneration in the striatum. To determine the expression pattern of N-TAF1 transcripts, we developed a specific monoclonal antibody against the N-TAF1 protein. Here we show that in the rat brain, N-TAF1 protein appears as a nuclear protein within subsets of neurons in multiple brain regions. Of particular interest is that in the striatum, the nuclei possessing N-TAF1 protein are largely within medium spiny neurons, and they are distributed preferentially, though not exclusively, in the striosome compartment. The compartmental preference and cell type-selective distribution of N-TAF1 protein in the striatum are strikingly similar to the patterns of neuronal loss in the striatum of DYT3 patients. Our findings suggest that the distribution of N-TAF1 protein could represent a key molecular characteristic contributing to the pattern of striatal degeneration in DYT3 dystonia.

Olfactory type G-protein alpha subunit in striosome-matrix dopamine systems in adult mice.

There is a growing body of evidence that striosome-matrix dopamine systems are tightly linked with motor and behavioral brain functions and disorders. In this study, we used an immunohistochemical method to show differential expression of the olfactory type G-protein alpha subunit (Galphaolf) that involves in the coupling of dopamine D1 receptor with adenylyl cyclase in the striatal compartments of adult mice, and observed heightened density of Galphaolf labeling in the striosomes relative to the matrix compartment. Our findings suggest that Galphaolf could be one of the key molecules for controlling differential responses of the striosome and matrix compartments to dopamine D1 receptor signaling in the striatum of adult mice.