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Protein

Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit STT3B

Gene

STT3B

Organism
Homo sapiens (Human)
Status
Reviewed-Annotation score: -Experimental evidence at protein leveli

Functioni

Catalytic subunit of the oligosaccharyl transferase (OST) complex that catalyzes the initial transfer of a defined glycan (Glc3Man9GlcNAc2 in eukaryotes) from the lipid carrier dolichol-pyrophosphate to an asparagine residue within an Asn-X-Ser/Thr consensus motif in nascent polypeptide chains, the first step in protein N-glycosylation. N-glycosylation occurs cotranslationally and the complex associates with the Sec61 complex at the channel-forming translocon complex that mediates protein translocation across the endoplasmic reticulum (ER). All subunits are required for a maximal enzyme activity. This subunit contains the active site and the acceptor peptide and donor lipid-linked oligosaccharide (LLO) binding pockets (By similarity). STT3B is present in a small subset of OST complexes and mediates both cotranslational and post-translational N-glycosylation of target proteins: STT3B-containing complexes are required for efficient post-translational glycosylation and while they are less competent than STT3A-containing complexes for cotranslational glycosylation, they have the ability to mediate glycosylation of some nascent sites that are not accessible for STT3A. STT3B-containing complexes also act post-translationally and mediate modification of skipped glycosylation sites in unfolded proteins. Plays a role in ER-associated degradation (ERAD) pathway that mediates ubiquitin-dependent degradation of misfolded endoplasmic reticulum proteins by mediating N-glycosylation of unfolded proteins, which are then recognized by the ERAD pathway and targeted for degradation. Mediates glycosylation of the disease variant AMYL-TTR 'Asp-38' of TTR at 'Asn-118', leading to its degradation (PubMed:19167329, PubMed:22607976).By similarity2 Publications

Catalytic activityi

Dolichyl diphosphooligosaccharide + [protein]-L-asparagine = dolichyl diphosphate + a glycoprotein with the oligosaccharide chain attached by N-beta-D-glycosyl linkage to a protein L-asparagine.By similarity

Cofactori

Mg2+By similarity, Mn2+By similarity

Pathwayi: protein glycosylation

This protein is involved in the pathway protein glycosylation, which is part of Protein modification.By similarity
View all proteins of this organism that are known to be involved in the pathway protein glycosylation and in Protein modification.

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Metal bindingi103ManganeseBy similarity1
Binding sitei103Target acceptor peptideBy similarity1
Sitei214Important for catalytic activityBy similarity1
Metal bindingi221ManganeseBy similarity1
Metal bindingi223ManganeseBy similarity1
Binding sitei405Target acceptor peptideBy similarity1
Binding sitei459Lipid-linked oligosaccharideBy similarity1
Binding sitei609Lipid-linked oligosaccharideBy similarity1
Binding sitei674Target acceptor peptideBy similarity1

GO - Molecular functioni

  • dolichyl-diphosphooligosaccharide-protein glycotransferase activity Source: UniProtKB
  • metal ion binding Source: UniProtKB-KW

GO - Biological processi

Keywordsi

Molecular functionGlycosyltransferase, Transferase
LigandMagnesium, Metal-binding

Enzyme and pathway databases

SignaLinkiQ8TCJ2
UniPathwayi
UPA00378

Protein family/group databases

CAZyiGT66 Glycosyltransferase Family 66

Names & Taxonomyi

Protein namesi
Recommended name:
Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit STT3B (EC:2.4.99.18)
Short name:
Oligosaccharyl transferase subunit STT3B
Short name:
STT3-B
Alternative name(s):
Source of immunodominant MHC-associated peptides homolog
Gene namesi
Name:STT3B
Synonyms:SIMP
OrganismiHomo sapiens (Human)
Taxonomic identifieri9606 [NCBI]
Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo
Proteomesi
  • UP000005640 Componenti: Chromosome 3

Organism-specific databases

EuPathDBiHostDB:ENSG00000163527.9
HGNCiHGNC:30611 STT3B
MIMi608605 gene
neXtProtiNX_Q8TCJ2

Subcellular locationi

Extracellular region or secreted Cytosol Plasma membrane Cytoskeleton Lysosome Endosome Peroxisome ER Golgi apparatus Nucleus Mitochondrion Manual annotation Automatic computational assertionGraphics by Christian Stolte; Source: COMPARTMENTS

Topology

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Topological domaini2 – 41CytoplasmicCuratedAdd BLAST40
Transmembranei42 – 86HelicalBy similarityAdd BLAST45
Topological domaini87 – 173LumenalCuratedAdd BLAST87
Transmembranei174 – 192HelicalBy similarityAdd BLAST19
Topological domaini193 – 194CytoplasmicCurated2
Transmembranei195 – 212HelicalBy similarityAdd BLAST18
Topological domaini213 – 223LumenalCuratedAdd BLAST11
Transmembranei224 – 243HelicalBy similarityAdd BLAST20
Topological domaini244 – 245CytoplasmicCurated2
Transmembranei246 – 260HelicalBy similarityAdd BLAST15
Topological domaini261 – 265LumenalCurated5
Transmembranei266 – 282HelicalBy similarityAdd BLAST17
Topological domaini283 – 287CytoplasmicCurated5
Transmembranei288 – 313HelicalBy similarityAdd BLAST26
Topological domaini314 – 321LumenalCurated8
Transmembranei322 – 341HelicalBy similarityAdd BLAST20
Topological domaini342 – 350CytoplasmicCurated9
Transmembranei351 – 371HelicalSequence analysisAdd BLAST21
Topological domaini372 – 410LumenalCuratedAdd BLAST39
Transmembranei411 – 433HelicalBy similarityAdd BLAST23
Topological domaini434 – 439CytoplasmicCurated6
Transmembranei440 – 456HelicalBy similarityAdd BLAST17
Topological domaini457 – 460LumenalCurated4
Transmembranei461 – 482HelicalBy similarityAdd BLAST22
Topological domaini483 – 526CytoplasmicCuratedAdd BLAST44
Transmembranei527 – 552HelicalBy similarityAdd BLAST26
Topological domaini553 – 826LumenalCuratedAdd BLAST274

Keywords - Cellular componenti

Endoplasmic reticulum, Membrane

Pathology & Biotechi

Involvement in diseasei

Congenital disorder of glycosylation 1X (CDG1X)1 Publication
The disease is caused by mutations affecting the gene represented in this entry.
Disease descriptionA form of congenital disorder of glycosylation, a multisystem disorder caused by a defect in glycoprotein biosynthesis and characterized by under-glycosylated serum glycoproteins. Congenital disorders of glycosylation result in a wide variety of clinical features, such as defects in the nervous system development, psychomotor retardation, dysmorphic features, hypotonia, coagulation disorders, and immunodeficiency. The broad spectrum of features reflects the critical role of N-glycoproteins during embryonic development, differentiation, and maintenance of cell functions.
See also OMIM:615597

Keywords - Diseasei

Congenital disorder of glycosylation

Organism-specific databases

DisGeNETi201595
MalaCardsiSTT3B
MIMi615597 phenotype
OpenTargetsiENSG00000163527
Orphaneti370924 STT3B-CDG
PharmGKBiPA143485625

Polymorphism and mutation databases

BioMutaiSTT3B
DMDMi74715800

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Initiator methionineiRemovedCombined sources
ChainiPRO_00002460012 – 826Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit STT3BAdd BLAST825

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei2N-acetylalanineCombined sources1
Modified residuei13PhosphoserineBy similarity1
Modified residuei18PhosphoserineCombined sources1
Modified residuei29PhosphoserineCombined sources1
Modified residuei498PhosphoserineCombined sources1
Modified residuei499PhosphoserineCombined sources1
Glycosylationi616N-linked (GlcNAc...) asparaginePROSITE-ProRule annotation1
Glycosylationi623N-linked (GlcNAc...) asparagine1 Publication1
Glycosylationi627N-linked (GlcNAc...) (high mannose) asparagine1 Publication1
Glycosylationi641N-linked (GlcNAc...) asparaginePROSITE-ProRule annotation1

Keywords - PTMi

Acetylation, Glycoprotein, Phosphoprotein

Proteomic databases

EPDiQ8TCJ2
MaxQBiQ8TCJ2
PaxDbiQ8TCJ2
PeptideAtlasiQ8TCJ2
PRIDEiQ8TCJ2
ProteomicsDBi74146

PTM databases

GlyConnecti1189
iPTMnetiQ8TCJ2
PhosphoSitePlusiQ8TCJ2
SwissPalmiQ8TCJ2

Expressioni

Tissue specificityi

Expressed in heart, brain, placenta, lung, liver, muscle, kidney and pancreas. Expressed in skin fibroblasts (at protein level).1 Publication

Gene expression databases

BgeeiENSG00000163527 Expressed in 209 organ(s), highest expression level in metanephros
CleanExiHS_STT3B
GenevisibleiQ8TCJ2 HS

Organism-specific databases

HPAiHPA036448
HPA036646

Interactioni

Subunit structurei

Component of the oligosaccharyltransferase (OST) complex. OST exists in two different complex forms which contain common core subunits RPN1, RPN2, OST48, OST4, DAD1 and TMEM258, either STT3A or STT3B as catalytic subunits, and form-specific accessory subunits. OST can form stable complexes with the Sec61 complex or with both the Sec61 and TRAP complexes (By similarity).By similarityCurated2 Publications

Protein-protein interaction databases

BioGridi128394, 43 interactors
CORUMiQ8TCJ2
IntActiQ8TCJ2, 33 interactors
MINTiQ8TCJ2
STRINGi9606.ENSP00000295770

Structurei

3D structure databases

ProteinModelPortaliQ8TCJ2
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Region

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Regioni604 – 606Target acceptor peptide bindingBy similarity3

Motif

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Motifi101 – 103DXD motif 1By similarity3
Motifi221 – 223DXD motif 2By similarity3
Motifi402 – 405SVSE motifBy similarity4
Motifi604 – 608WWDYG motifBy similarity5
Motifi671 – 678DK motifBy similarity8

Domaini

Despite low primary sequence conservation between eukaryotic catalytic subunits and bacterial and archaeal single subunit OSTs (ssOST), structural comparison revealed several common motifs at spatially equivalent positions, like the DXD motif 1 on the external loop 1 and the DXD motif 2 on the external loop 2 involved in binding of the metal ion cofactor and the carboxamide group of the acceptor asparagine, the conserved Glu residue of the TIXE/SVSE motif on the external loop 5 involved in catalysis, as well as the WWDYG and the DK/MI motifs in the globular domain that define the binding pocket for the +2 Ser/Thr of the acceptor sequon. In bacterial ssOSTs, an Arg residue was found to interact with a negatively charged side chain at the -2 position of the sequon. This Arg is conserved in bacterial enzymes and correlates with an extended sequon requirement (Asp-X-Asn-X-Ser/Thr) for bacterial N-glycosylation.By similarity

Sequence similaritiesi

Belongs to the STT3 family.Curated

Keywords - Domaini

Transmembrane, Transmembrane helix

Phylogenomic databases

eggNOGiKOG2292 Eukaryota
COG1287 LUCA
GeneTreeiENSGT00390000015238
HOGENOMiHOG000157471
HOVERGENiHBG010606
InParanoidiQ8TCJ2
KOiK07151
OMAiNYRATAY
OrthoDBiEOG091G02DB
PhylomeDBiQ8TCJ2
TreeFamiTF300822

Family and domain databases

InterProiView protein in InterPro
IPR003674 Oligo_trans_STT3
PfamiView protein in Pfam
PF02516 STT3, 1 hit

Sequencei

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

Q8TCJ2-1 [UniParc]FASTAAdd to basket
« Hide
        10         20         30         40         50
MAEPSAPESK HKSSLNSSPW SGLMALGNSR HGHHGPGAQC AHKAAGGAAP
60 70 80 90 100
PKPAPAGLSG GLSQPAGWQS LLSFTILFLA WLAGFSSRLF AVIRFESIIH
110 120 130 140 150
EFDPWFNYRS THHLASHGFY EFLNWFDERA WYPLGRIVGG TVYPGLMITA
160 170 180 190 200
GLIHWILNTL NITVHIRDVC VFLAPTFSGL TSISTFLLTR ELWNQGAGLL
210 220 230 240 250
AACFIAIVPG YISRSVAGSF DNEGIAIFAL QFTYYLWVKS VKTGSVFWTM
260 270 280 290 300
CCCLSYFYMV SAWGGYVFII NLIPLHVFVL LLMQRYSKRV YIAYSTFYIV
310 320 330 340 350
GLILSMQIPF VGFQPIRTSE HMAAAGVFAL LQAYAFLQYL RDRLTKQEFQ
360 370 380 390 400
TLFFLGVSLA AGAVFLSVIY LTYTGYIAPW SGRFYSLWDT GYAKIHIPII
410 420 430 440 450
ASVSEHQPTT WVSFFFDLHI LVCTFPAGLW FCIKNINDER VFVALYAISA
460 470 480 490 500
VYFAGVMVRL MLTLTPVVCM LSAIAFSNVF EHYLGDDMKR ENPPVEDSSD
510 520 530 540 550
EDDKRNQGNL YDKAGKVRKH ATEQEKTEEG LGPNIKSIVT MLMLMLLMMF
560 570 580 590 600
AVHCTWVTSN AYSSPSVVLA SYNHDGTRNI LDDFREAYFW LRQNTDEHAR
610 620 630 640 650
VMSWWDYGYQ IAGMANRTTL VDNNTWNNSH IALVGKAMSS NETAAYKIMR
660 670 680 690 700
TLDVDYVLVI FGGVIGYSGD DINKFLWMVR IAEGEHPKDI RESDYFTPQG
710 720 730 740 750
EFRVDKAGSP TLLNCLMYKM SYYRFGEMQL DFRTPPGFDR TRNAEIGNKD
760 770 780 790 800
IKFKHLEEAF TSEHWLVRIY KVKAPDNRET LDHKPRVTNI FPKQKYLSKK
810 820
TTKRKRGYIK NKLVFKKGKK ISKKTV
Length:826
Mass (Da):93,674
Last modified:June 1, 2002 - v1
Checksum:iB70C221C7CBEB798
GO

Sequence cautioni

The sequence AAH15880 differs from that shown. Reason: Erroneous initiation. Translation N-terminally extended.Curated
The sequence BAB55370 differs from that shown. Reason: Erroneous initiation. Translation N-terminally extended.Curated
The sequence BAC11581 differs from that shown. Reason: Erroneous initiation. Translation N-terminally extended.Curated

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence conflicti822S → F in AAH15880 (PubMed:15489334).Curated1

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AY074880 mRNA Translation: AAL71884.1
AC104643 Genomic DNA No translation available.
AK027789 mRNA Translation: BAB55370.1 Different initiation.
AK075380 mRNA Translation: BAC11581.1 Different initiation.
BC015880 mRNA Translation: AAH15880.1 Different initiation.
CCDSiCCDS2650.1
RefSeqiNP_849193.1, NM_178862.2
UniGeneiHs.475812

Genome annotation databases

EnsembliENST00000295770; ENSP00000295770; ENSG00000163527
GeneIDi201595
KEGGihsa:201595
UCSCiuc011axe.3 human

Similar proteinsi

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AY074880 mRNA Translation: AAL71884.1
AC104643 Genomic DNA No translation available.
AK027789 mRNA Translation: BAB55370.1 Different initiation.
AK075380 mRNA Translation: BAC11581.1 Different initiation.
BC015880 mRNA Translation: AAH15880.1 Different initiation.
CCDSiCCDS2650.1
RefSeqiNP_849193.1, NM_178862.2
UniGeneiHs.475812

3D structure databases

ProteinModelPortaliQ8TCJ2
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

BioGridi128394, 43 interactors
CORUMiQ8TCJ2
IntActiQ8TCJ2, 33 interactors
MINTiQ8TCJ2
STRINGi9606.ENSP00000295770

Protein family/group databases

CAZyiGT66 Glycosyltransferase Family 66

PTM databases

GlyConnecti1189
iPTMnetiQ8TCJ2
PhosphoSitePlusiQ8TCJ2
SwissPalmiQ8TCJ2

Polymorphism and mutation databases

BioMutaiSTT3B
DMDMi74715800

Proteomic databases

EPDiQ8TCJ2
MaxQBiQ8TCJ2
PaxDbiQ8TCJ2
PeptideAtlasiQ8TCJ2
PRIDEiQ8TCJ2
ProteomicsDBi74146

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsembliENST00000295770; ENSP00000295770; ENSG00000163527
GeneIDi201595
KEGGihsa:201595
UCSCiuc011axe.3 human

Organism-specific databases

CTDi201595
DisGeNETi201595
EuPathDBiHostDB:ENSG00000163527.9
GeneCardsiSTT3B
HGNCiHGNC:30611 STT3B
HPAiHPA036448
HPA036646
MalaCardsiSTT3B
MIMi608605 gene
615597 phenotype
neXtProtiNX_Q8TCJ2
OpenTargetsiENSG00000163527
Orphaneti370924 STT3B-CDG
PharmGKBiPA143485625
GenAtlasiSearch...

Phylogenomic databases

eggNOGiKOG2292 Eukaryota
COG1287 LUCA
GeneTreeiENSGT00390000015238
HOGENOMiHOG000157471
HOVERGENiHBG010606
InParanoidiQ8TCJ2
KOiK07151
OMAiNYRATAY
OrthoDBiEOG091G02DB
PhylomeDBiQ8TCJ2
TreeFamiTF300822

Enzyme and pathway databases

UniPathwayi
UPA00378

SignaLinkiQ8TCJ2

Miscellaneous databases

ChiTaRSiSTT3B human
GeneWikiiSTT3B
GenomeRNAii201595
PROiPR:Q8TCJ2
SOURCEiSearch...

Gene expression databases

BgeeiENSG00000163527 Expressed in 209 organ(s), highest expression level in metanephros
CleanExiHS_STT3B
GenevisibleiQ8TCJ2 HS

Family and domain databases

InterProiView protein in InterPro
IPR003674 Oligo_trans_STT3
PfamiView protein in Pfam
PF02516 STT3, 1 hit
ProtoNetiSearch...

Entry informationi

Entry nameiSTT3B_HUMAN
AccessioniPrimary (citable) accession number: Q8TCJ2
Secondary accession number(s): Q96JZ4, Q96KY7
Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 11, 2006
Last sequence update: June 1, 2002
Last modified: November 7, 2018
This is version 129 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program
DisclaimerAny medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care.

Miscellaneousi

Keywords - Technical termi

Complete proteome, Reference proteome

Documents

  1. SIMILARITY comments
    Index of protein domains and families
  2. Human chromosome 3
    Human chromosome 3: entries, gene names and cross-references to MIM
  3. MIM cross-references
    Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot
  4. PATHWAY comments
    Index of metabolic and biosynthesis pathways
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Main funding by: National Institutes of Health

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