OSTC (oligosaccharyltransferase complex non-catalytic subunit) is a non-catalytic adapter subunit of the STT3A-containing oligosaccharyl transferase (OST-A) complex located on chromosome 4. OSTC functions primarily as an adapter protein that anchors the OST-A complex to the Sec61 translocon complex at the endoplasmic reticulum (ER) membrane 1. The OST-A complex catalyzes cotranslational N-linked glycosylation by transferring a defined glycan structure (Glc(3)Man(9)GlcNAc(2)) from dolichol-pyrophosphate to asparagine residues in nascent polypeptide chains within Asn-X-Ser/Thr consensus motifs. OSTC exists as part of multiple oligomeric OST subcomplexes ranging from 500-700 kDa that exhibit differential ribosome affinities 1. Expression of OSTC is upregulated during heat shock stress, with temporal changes in protein levels varying across different tissues, particularly in the cerebellum where induction parallels AKT activation 2. OSTC mRNA is ubiquitously expressed with abundant levels in placenta and liver 2. Additionally, OSTC is transcriptionally regulated by ZBTB24, a zinc-finger transcription factor implicated in epigenetic control 3. The physiological significance of OSTC in protein glycosylation suggests importance for proper protein folding and trafficking during the stress response.