ID   SIA8B_RAT               Reviewed;         375 AA.
AC   Q07977; Q64688;
DT   01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   27-MAR-2024, entry version 128.
DE   RecName: Full=Alpha-2,8-sialyltransferase 8B {ECO:0000305};
DE            EC=2.4.3.- {ECO:0000250|UniProtKB:Q92186};
DE   AltName: Full=Sialyltransferase 8B;
DE            Short=SIAT8-B;
DE   AltName: Full=Sialyltransferase St8Sia II;
DE            Short=ST8SiaII;
DE   AltName: Full=Sialyltransferase X {ECO:0000250|UniProtKB:Q92186};
DE            Short=STX {ECO:0000250|UniProtKB:Q92186};
GN   Name=St8sia2 {ECO:0000312|RGD:621843};
GN   Synonyms=Siat8b, Stx {ECO:0000250|UniProtKB:Q92186};
OS   Rattus norvegicus (Rat).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Euarchontoglires; Glires; Rodentia; Myomorpha; Muroidea; Muridae;
OC   Murinae; Rattus.
OX   NCBI_TaxID=10116;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], TISSUE SPECIFICITY, AND DEVELOPMENTAL STAGE.
RC   STRAIN=Sprague-Dawley; TISSUE=Brain;
RX   PubMed=7685014; DOI=10.1016/s0021-9258(19)50227-7;
RA   Livingston B.D., Paulson J.C.;
RT   "Polymerase chain reaction cloning of a developmentally regulated member of
RT   the sialyltransferase gene family.";
RL   J. Biol. Chem. 268:11504-11507(1993).
CC   -!- FUNCTION: Catalyzes the transfer of a sialic acid from a CMP-linked
CC       sialic acid donor onto a terminal alpha-2,3-, alpha-2,6-, or alpha-2,8-
CC       linked sialic acid of an N-linked glycan acceptor through alpha-2,8-
CC       linkages. Therefore, participates in polysialic acid synthesis on
CC       various sialylated N-acetyllactosaminyl oligosaccharides (alpha-2,3-,
CC       alpha-2,6-, or alpha-2,8-linked sialic acid), including NCAM1, NCAM1 N-
CC       glycans, FETUB N-glycans, and to a lesser extent sialylparagloboside
CC       (SPG) and AHSG, which does not require the initial addition of an alpha
CC       2,8-sialic acid (By similarity). However, does not exhibit sialic acid-
CC       polymerase activity (By similarity). Catalyzes polysialic acid
CC       synthesis in the hippocampal on NCAM1 and supports neurite outgrowth
CC       (By similarity). ST8SIA2-mediated polysialylation influences on
CC       oligodendrocyte differentiation and may promote the integrity of myelin
CC       and axons (By similarity). {ECO:0000250|UniProtKB:O35696,
CC       ECO:0000250|UniProtKB:Q92186}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=[N-acetyl-alpha-D-neuraminosyl-(2->8)](n) + CMP-N-acetyl-beta-
CC         neuraminate = [N-acetyl-alpha-D-neuraminosyl-(2->8)](n+1) + CMP +
CC         H(+); Xref=Rhea:RHEA:77367, Rhea:RHEA-COMP:14315, Rhea:RHEA-
CC         COMP:18878, ChEBI:CHEBI:15378, ChEBI:CHEBI:57812, ChEBI:CHEBI:60377,
CC         ChEBI:CHEBI:139252; Evidence={ECO:0000250|UniProtKB:Q92186};
CC       PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:77368;
CC         Evidence={ECO:0000250|UniProtKB:Q92186};
CC   -!- PATHWAY: Protein modification; protein glycosylation.
CC       {ECO:0000250|UniProtKB:Q92186}.
CC   -!- SUBCELLULAR LOCATION: Golgi apparatus membrane
CC       {ECO:0000250|UniProtKB:Q92186}; Single-pass type II membrane protein
CC       {ECO:0000250|UniProtKB:Q92186}. Secreted
CC       {ECO:0000250|UniProtKB:Q92186}. Cell membrane
CC       {ECO:0000250|UniProtKB:Q92186}. Note=Also trafficks to the cell
CC       surface. {ECO:0000250|UniProtKB:Q92186}.
CC   -!- TISSUE SPECIFICITY: Expressed only in newborn brain.
CC       {ECO:0000269|PubMed:7685014}.
CC   -!- DEVELOPMENTAL STAGE: Newborn. {ECO:0000269|PubMed:7685014}.
CC   -!- PTM: Autopolysialylated. Autopolysialylation is not a prerequisite for
CC       the polysialylation acitity, but enhances the polysialylation acitity.
CC       {ECO:0000250|UniProtKB:Q92186}.
CC   -!- SIMILARITY: Belongs to the glycosyltransferase 29 family.
CC       {ECO:0000305}.
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DR   EMBL; L13445; AAA42147.1; -; mRNA.
DR   PIR; A46727; A46727.
DR   RefSeq; NP_476497.1; NM_057156.1.
DR   AlphaFoldDB; Q07977; -.
DR   SMR; Q07977; -.
DR   CAZy; GT29; Glycosyltransferase Family 29.
DR   GlyCosmos; Q07977; 6 sites, No reported glycans.
DR   GlyGen; Q07977; 6 sites.
DR   iPTMnet; Q07977; -.
DR   PhosphoSitePlus; Q07977; -.
DR   Ensembl; ENSRNOT00000113519.1; ENSRNOP00000092932.1; ENSRNOG00000065528.1.
DR   Ensembl; ENSRNOT00065047942; ENSRNOP00065039350; ENSRNOG00065027807.
DR   GeneID; 117523; -.
DR   KEGG; rno:117523; -.
DR   UCSC; RGD:621843; rat.
DR   AGR; RGD:621843; -.
DR   CTD; 8128; -.
DR   RGD; 621843; St8sia2.
DR   GeneTree; ENSGT01030000234535; -.
DR   InParanoid; Q07977; -.
DR   OMA; ATRFCNT; -.
DR   OrthoDB; 5348004at2759; -.
DR   PhylomeDB; Q07977; -.
DR   Reactome; R-RNO-4085001; Sialic acid metabolism.
DR   Reactome; R-RNO-419037; NCAM1 interactions.
DR   Reactome; R-RNO-975577; N-Glycan antennae elongation.
DR   UniPathway; UPA00378; -.
DR   PRO; PR:Q07977; -.
DR   Proteomes; UP000002494; Chromosome 1.
DR   GO; GO:0005769; C:early endosome; ISO:RGD.
DR   GO; GO:0005576; C:extracellular region; ISS:UniProtKB.
DR   GO; GO:0005794; C:Golgi apparatus; ISS:UniProtKB.
DR   GO; GO:0000139; C:Golgi membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0048471; C:perinuclear region of cytoplasm; IDA:RGD.
DR   GO; GO:0055037; C:recycling endosome; ISO:RGD.
DR   GO; GO:0003828; F:alpha-N-acetylneuraminate alpha-2,8-sialyltransferase activity; ISS:UniProtKB.
DR   GO; GO:0008373; F:sialyltransferase activity; IMP:RGD.
DR   GO; GO:0001574; P:ganglioside biosynthetic process; ISO:RGD.
DR   GO; GO:0006491; P:N-glycan processing; ISO:RGD.
DR   GO; GO:0030182; P:neuron differentiation; IEP:RGD.
DR   GO; GO:1990138; P:neuron projection extension; IMP:RGD.
DR   GO; GO:0009311; P:oligosaccharide metabolic process; ISO:RGD.
DR   GO; GO:0043525; P:positive regulation of neuron apoptotic process; IDA:RGD.
DR   GO; GO:0051965; P:positive regulation of synapse assembly; IMP:RGD.
DR   GO; GO:0006486; P:protein glycosylation; ISO:RGD.
DR   GO; GO:0042220; P:response to cocaine; IEP:RGD.
DR   GO; GO:0097503; P:sialylation; ISS:UniProtKB.
DR   Gene3D; 3.90.1480.20; Glycosyl transferase family 29; 1.
DR   InterPro; IPR001675; Glyco_trans_29.
DR   InterPro; IPR038578; GT29-like_sf.
DR   InterPro; IPR012163; Sialyl_trans.
DR   PANTHER; PTHR11987; ALPHA-2,8-SIALYLTRANSFERASE; 1.
DR   PANTHER; PTHR11987:SF30; ALPHA-2,8-SIALYLTRANSFERASE 8B; 1.
DR   Pfam; PF00777; Glyco_transf_29; 1.
DR   PIRSF; PIRSF005557; Sialyl_trans; 1.
PE   2: Evidence at transcript level;
KW   Cell membrane; Disulfide bond; Glycoprotein; Glycosyltransferase;
KW   Golgi apparatus; Membrane; Nucleotide-binding; Reference proteome;
KW   Secreted; Signal-anchor; Transferase; Transmembrane; Transmembrane helix.
FT   CHAIN           1..375
FT                   /note="Alpha-2,8-sialyltransferase 8B"
FT                   /id="PRO_0000149288"
FT   TOPO_DOM        1..6
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        7..23
FT                   /note="Helical; Signal-anchor for type II membrane protein"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        24..375
FT                   /note="Lumenal"
FT                   /evidence="ECO:0000255"
FT   ACT_SITE        346
FT                   /note="Proton donor/acceptor"
FT                   /evidence="ECO:0000250|UniProtKB:O43173"
FT   BINDING         162
FT                   /ligand="CMP-N-acetyl-beta-neuraminate"
FT                   /ligand_id="ChEBI:CHEBI:57812"
FT                   /evidence="ECO:0000250|UniProtKB:O43173"
FT   BINDING         185
FT                   /ligand="CMP-N-acetyl-beta-neuraminate"
FT                   /ligand_id="ChEBI:CHEBI:57812"
FT                   /evidence="ECO:0000250|UniProtKB:O43173"
FT   BINDING         294
FT                   /ligand="CMP-N-acetyl-beta-neuraminate"
FT                   /ligand_id="ChEBI:CHEBI:57812"
FT                   /evidence="ECO:0000250|UniProtKB:O43173"
FT   BINDING         295
FT                   /ligand="CMP-N-acetyl-beta-neuraminate"
FT                   /ligand_id="ChEBI:CHEBI:57812"
FT                   /evidence="ECO:0000250|UniProtKB:O43173"
FT   BINDING         296
FT                   /ligand="CMP-N-acetyl-beta-neuraminate"
FT                   /ligand_id="ChEBI:CHEBI:57812"
FT                   /evidence="ECO:0000250|UniProtKB:O43173"
FT   BINDING         316
FT                   /ligand="CMP-N-acetyl-beta-neuraminate"
FT                   /ligand_id="ChEBI:CHEBI:57812"
FT                   /evidence="ECO:0000250|UniProtKB:O43173"
FT   BINDING         329
FT                   /ligand="CMP-N-acetyl-beta-neuraminate"
FT                   /ligand_id="ChEBI:CHEBI:57812"
FT                   /evidence="ECO:0000250|UniProtKB:O43173"
FT   BINDING         330
FT                   /ligand="CMP-N-acetyl-beta-neuraminate"
FT                   /ligand_id="ChEBI:CHEBI:57812"
FT                   /evidence="ECO:0000250|UniProtKB:O43173"
FT   CARBOHYD        60
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        72
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        89
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        134
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        219
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        234
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   DISULFID        157..307
FT                   /evidence="ECO:0000250|UniProtKB:O43173"
FT   DISULFID        171..371
FT                   /evidence="ECO:0000250|UniProtKB:O43173"
SQ   SEQUENCE   375 AA;  42400 MW;  F7B3AC1E1E503675 CRC64;
     MQLQFRSWML AALTLLVVFL IFADISEIEE EIGNSGGRGT IRSAVNSLHS KSNRAEVVIN
     GSSLPAVADR SNESLKHSIQ PASSKWRHNQ TLSLRIRKQI LKFLDAEKDI SVLKGTLKPG
     DIIHYIFDRD STMNVSQNLY ELLPRTSPLK NKHFQTCAIV GNSGVLLNSG CGQEIDTHSF
     VIRCNLAPVQ EYARDVGLKT DLVTMNPSVI QRAFEDLVNA TWREKLLQRL HGLNGSILWI
     PAFMARGGKE RVEWVNALIL KHHVNVRTAY PSLRLLHAVR GYWLTNKVHI KRPTTGLLMY
     TLATRFCNQI YLYGFWPFPL DQNQNPVKYH YYDSLKYGYT SQASPHTMPL EFKALKSLHE
     QGALKLTVGQ CDGAT
//