Summary

This protein is a subunit of the OST complex, which attaches a 14-sugars N-glycan precursor to proteins being translated in the ER,to a Asn-X-Thr/Ser sequon.

High impact information on STT3B

• Relevant key features of SIMP/STT3B are its lysine-rich region, its propensity to misfold and its location in the ER membrane in close proximity to the immunoproteasome [1].
• We show that the endoplasmic reticulum (ER)-associated degradation pathway and MHC I processing intersect at SIMP/STT3B [1].
• We also identified a bipartite nuclear targeting sequence in the C-terminal tail of STT3-B that is absent in STT3-A [2].
• Strikingly, while the difference in the amino acid sequence 770-778 encoded by the two SIMP alleles represents a very conservative substitution, these allelic peptides were not crossreactive at the CTL level, and both peptides were immunodominant when presented to mice homozygous for the opposite allele [3].
• Phenotypic and genotypic analyses among eight strains of mice revealed a precise correlation between susceptibility or resistance to B6(dom1)-specific cytotoxic T lymphocytes (CTLs) and the presence of a Glu vs Asp amino acid at position 776 of the SIMP protein, respectively [3].

Analytical, diagnostic and therapeutic context of STT3B

• When topical therapy with a 1 mmol/l solution of SIMP was initiated after corneal ulceration had progressed to a mid-stromal level (clinical score of 2), there was no significant difference in the progression of corneal ulceration between the treated vs. control group after 6 d of therapy [4].
• We demonstrated that there was good agreement between LVEF determined using both MANUAL SIMP and semiautomated endocardial border detection, and radionuclide angiography (standard of comparison) [5].

References