N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase; GalNAc4S-6ST; B-cell RAG-associated gene protein; hBRAG, (GALNAC4S6ST, BRAG, CHST15, KIAA0598)

Function

• sulfotransferase
• transfers sulfate from 3'-phosphoadenosine 5'-phosphosulfate (PAPS) to the C-6 hydroxyl group of the GalNAc 4-sulfate residue of chondroitin sulfate A & forms chondroitin sulfate E containing GlcA-GalNAc(4,6-SO4) repeating units
• transfers sulfate to a unique nonreducing terminal sequence, GalNAc(4SO4)-GlcA(2SO4)-GalNAc(6SO4), to yield a highly sulfated structure similar to the structure found in thrombomodulin chondroitin sulfate
• B-cell receptor involved in BCR ligation-mediated early activation & mediates regulatory signals key to B-cell development &/or regulate of B-cell-specific RAG expression (putative)
• interacts with phosphorylated proteins in resting B-cells, including HCK (putative)
• inhibited by phenyl beta-GalNAc(4,6-SO4)

3'-phosphoadenylyl sulfate + dermatan
        <-->
adenosine 3',5'-bisphosphate + dermatan 6'-sulfate

3'-phosphoadenylyl sulfate + chondroitin
        <-->
adenosine 3',5'-bisphosphate + chondroitin 6'-sulfate

Cofactors:

• divalent metal cations
• glutathione

Structure

• homodimer, disulfide-linked
• glycosylated

Compartment

• Golgi membrane, cell surface (minor)
• colocalizes with RAG1 in pro-B, pre-B, & mature B-cell lines

Alternative splicing

named isoforms=2

Expression

• expressed in B-cell-enriched tissues, including fetal & adult spleen, lymph node, tonsil, bone marrow & peripheral leukocytes
• not expressed in fetal or adult thymus, T-cells

More general terms

• sulfotransferase
• membrane protein
• glycoprotein

Database

• OMIM: https://mirror.omim.org/entry/608277
• UniProt: http://www.uniprot.org/uniprot/Q7LFX5.html