Search Results

Overview

Uniprot IDQ8TCJ2
Protein NameDolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit STT3B
Gene NameSTT3B
OrganismHomo sapiens

Kla Sites from experimental identification

Position Flanking peptide
513 NQGNLYDKAGKVRKH
516 NLYDKAGKVRKHATE

Function

Catalytic subunit of the oligosaccharyl transferase (OST) complex that catalyzes the initial transfer of a defined glycan (Glc(3)Man(9)GlcNAc(2) 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 (PubMed:19167329, PubMed:31296534, PubMed:31831667, PubMed:39509507). 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) (PubMed:19167329, PubMed:31296534, PubMed:31831667, PubMed:39509507). 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 (PubMed:19167329, PubMed:31296534, PubMed:31831667, PubMed:39509507). STT3B is present in a small subset of OST complexes (OST-B) 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 (PubMed:19167329, PubMed:22607976, PubMed:31296534, PubMed:39509507). STT3B-containing complexes also act post-translationally and mediate modification of skipped glycosylation sites in unfolded proteins (PubMed:19167329, PubMed:22607976, PubMed:39509507). 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 (PubMed:19167329, PubMed:22607976). Mediates glycosylation of the disease variant AMYL-TTR 'Asp-38' of TTR at 'Asn-118', leading to its degradation (PubMed:19167329, PubMed:22607976)

Protein Sequence

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

Gene Ontology

Classification GO ID Description
Cellular Component GO:0005783 endoplasmic reticulum
Cellular Component GO:0005789 endoplasmic reticulum membrane
Cellular Component GO:0016020 membrane
Cellular Component GO:0008250 oligosaccharyltransferase complex
Cellular Component GO:0160227 oligosaccharyltransferase complex B
Cellular Component GO:0032991 protein-containing complex
Molecular Function GO:0004579 dolichyl-diphosphooligosaccharide-protein glycotransferase activity
Molecular Function GO:0046872 metal ion binding
Biological Process GO:0036503 ERAD pathway
Biological Process GO:0006516 glycoprotein catabolic process
Biological Process GO:0043687 post-translational protein modification
Biological Process GO:0180058 protein co-translational transfer of dolichol-linked oligosaccharide
Biological Process GO:0006487 protein N-linked glycosylation
Biological Process GO:0180057 protein post-translational transfer of dolichol-linked oligosaccharide
Biological Process GO:0006986 response to unfolded protein

Reference

[1] Yang Z, Yan C, Ma J, Peng P, Ren X et al.. Lactylome analysis suggests lactylation-dependent mechanisms of metabolic adaptation in hepatocellular carcinoma.. Nat Metab 5(1):61-79. 2023 Jan. PMID: 36593272.

[2] Guo X, Ren X, Yan C, Huang H. Quantitative Proteomics Reveals the Role of Lysine Lactylation in Lenalidomide-Resistance in Multiple Myeloma Cells.. ACS Chem Biol 20(7):1728-1738. 2025 Jul 18. PMID: 40590393.

[3] He J, Lai T, Zhou Z, Yang H, Lei Z et al.. Multiomics profiling reveals the involvement of protein lactylation in nonhomologous end joining pathway conferring radioresistance in lung adenocarcinoma cell.. Sci Rep 15(1):24651. 2025 Jul 9. PMID: 40634431.