Compartmentation of the mouse cerebellar cortex by sphingosine kinase.
Classic cerebellar anatomy is based on the characteristic array of lobes and lobules. However, there is substantial evidence to suggest that more fundamental architecture is built around arrays of parasagittal stripes, which encompass both the inputs and outputs of the Purkinje cells (PCs). Sphingosine kinase (SPHK) is an enzyme that converts sphingosine (Sph) into sphingosine-1-phosphate (S1P). Recent reports have indicated that ceramide, Sph, and S1P play a role in cell survival, growth, and differentiation in several cell types, including neurons. In this study, we examined the localization of SPHK in the mouse cerebellum by using immunohistochemistry. Anti-SPHK immunoreactivity appeared in the cerebellar molecular layer and the PC membranes. The staining pattern is striped. In the molecular layer, the staining pattern probably reflects dendritic spines and dendrites. By electron microscopy, peroxidase reaction product was deposited within dendrites especially along the plasma membranes near spines. Seen at higher magnification, the staining was in and near the postsynaptic complexes. By double immunostaining, the striped pattern of SPHK expression was shown to be identical to that revealed by anti-zebrin II, although the subcellular distribution within PC's is not. This is the first demonstration of the cerebellar compartmentation of an enzyme related to lipid metabolism, and as such, it provides an insight into the roles of SPHK and formation of S1P. The selective expression of SPHK in the zebrin II-immunoreactive PCs may explain their resistance to cell death when ceramide metabolism is disrupted, as in the acid sphingomyelinase knockout model of Niemann-Pick type A/B disease.
Terada
Nobuo
N
Department of Anatomy, Faculty of Medicine, University of Yamanashi, 1110 Shimokato, Tamaho, Yamanashi 409-3898, Japan. nobuot@yamanashi.ac.jp
Banno
Yoshiko
Y
Ohno
Nobuhiko
N
Fujii
Yasuhisa
Y
Murate
Takashi
T
Sarna
Justyna R
JR
Hawkes
Richard
R
Zea
Zagreb
Z
Baba
Takeshi
T
Ohno
Shinichi
S
D000595:Amino Acid Sequence; D000818:Animals; D064026:Calbindins; D002525:Cerebellar Cortex / Q000201:enzymology* / Q000648:ultrastructure; D007150:Immunohistochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000032:analysis; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism* / Q000648:ultrastructure; D011689:Purkinje Cells / Q000201:enzymology / Q000648:ultrastructure; D064030:S100 Calcium Binding Protein G / Q000032:analysis; D000099157:Sphingosine Kinase
D064026:Calbindins; D009419:Nerve Tissue Proteins; D017853:Phosphotransferases (Alcohol Group Acceptor); D064030:S100 Calcium Binding Protein G; D000099157:Sphingosine Kinase; C071871:zebrin II