sphingosine 1-phosphate receptor 5 (endothelial differentiation sphingolipid G-protein-coupled receptor 8, S1PR5, EDG8)
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Function
- receptor for the lysosphingolipid sphingosine 1-phosphate
- coupled to Gi, Go & G12 heteromeric G-proteins
- role in transformation of radial glial cells into astrocytes
- may affect proliferation of astrocytes
- membrane
Structure
- belongs to the G-protein coupled receptor 1 family
Alternative splicing
named isoforms=2
Expression
- widely expressed in the brain
- most prominently in corpus callosum
- detected in spleen, peripheral blood leukocytes, placenta, lung, aorta, fetal spleen
- isoform 1 is predominently expressed in peripheral tissues
- isoform 2 is expressed in brain, spleen & peripheral blood leucocytes
- at 24 weeks of gestation, fragments of radial glial fibers are positive within the cortical plate & subplate of allocortical areas - these positive fragments often appear enlarged as varicosities, some terminate at blood vessels
- between 28-30 weeks of gestation, all iso- & allocortical areas contain immunolabelled radial glial fibers revealing curvature next to sulci
- after 32 weeks of gestation, radial glial fibers gradually disappear; instead positive transitional stages between radial glia & astrocytes are found
Pathology
- overexpressed in large granular lymphocyte syndrome