Localization and Expression of Cytosolic Sulfotransferases (SULTs) in Normal Human Brain

Abstract

Cytosolic SULTs are a family of Phase II enzymes that catalyze the transfer of a sulfonate group (SO3−) from 3′‐phosphoadensoine 5′‐phoshosulphate (PAPS) to endogenous and xenobiotic compounds. Message for several of the SULT isoforms has been detected in brain; however, protein expression patterns have not been extensively characterized. Immunoblot analysis was performed on cytosolic fractions isolated from superior temporal gyrus, hippocampus, cerebellum, occipital pole, frontal pole and temporal pole regions of normal brains. SULT1A1 expression is highest in cerebellum and occipital pole, while SULT1A3 expression is highest in frontal and temporal poles. SULT2B1b expression was higher in cerebellum, frontal and temporal poles. SULT1B1 expression was also identified in all brain regions examined, whereas SULT1E1 and 2A1 expression has not been detected. Immunohistochemistry was performed on hippocampus, cerebellum, frontal cortex, temporal lobe and pituitary paraffin sections. SULT1A1, 1A3, and 2B1b localize primarily to neurons whereas SULT1B1 also localizes to non‐neuronal cells. The differences in expression pattern and cellular localization of the SULT isoforms may be associated with selective substrate conjugation and functions in the different brain regions. Research supported by PHS grant GM38953‐22 to CNF.