Premium
Post‐translational Modification and Nuclear Localization of Human Sulfotransferase (SULT) 2B1b
Author(s) -
Falany Charles N,
Dumas Nicole A.,
He Dongning,
Frost Andra R.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.921.12
Subject(s) - phosphorylation , nuclear localization sequence , nuclear protein , subcellular localization , biology , chromosomal translocation , nuclear transport , cell nucleus , gene , chemistry , microbiology and biotechnology , biochemistry , transcription factor
SULT2B1b is a novel SULT isoform with selectivity for the sulfation of 3β‐hdroxysteroids and cholesterol. SULT2B1b has a unique 53 amino acid 3′‐tail that undergoes Ser phosphorylation and is involved with nuclear translocation in BeWo choriocarcinoma cells. The human SULT2B1 gene encodes two messages utilizing different transcriptional start sites resulting in the incorporation of different first exons. Although both SULT2B1a and 2B1b messages are found in human tissues, only the SULT2B1b protein has been detected. SULT2B1b is present in nuclei of term placental synchiotrophoblast and normal and cancerous breast epithelial cells. The 3′‐tail of SULT2B1b is required for nuclear localization in BeWo cells. Deletion of the unique 3′‐tail prevents translocation to the nuclei. 2D electrophoresis indicates two charge variants of SULT2B1b in BeWo cells; however, the variants are not detected in SULT2B1b lacking the 3′‐tail. Phosphorylation of Ser248 in the 3′‐tail is associated with nuclear localization. Mutation of Ser248 to Ala blocks nuclear translocation of SULT2B1b. Treatment of BeWo cells expressing SULT2B1b with forskolin, a cAMP‐dependent PKA inducer, increases phosphorylation and nuclear localization. SULT2B1b is the first SULT to show post‐translational modification and nuclear localization suggesting a unique function in nuclei. Supported by PHS grant GM38953 to CNF.