The newly synthesized MHC class I heavy chain (HC) translocates into the endoplasmic reticulum (ER) and binds rapidly to calnexin (CNX), a transmembrane calcium-dependent lectin with chaperone activity. CNX recognizes and binds to an N-linked monoglycosylated Glc1Man9GlcNAc2 carbohydrate group found attached to the conserved Asn-86 in the HC. Interaction of HC with CNX promotes the formation of intrachain disulfide bonds. Another candidate ER chaperon protein is immunoglobulin binding protein (BiP), found to associate with HC in the absence of CNX. These chaperones can cooperate in protein folding and prevention of aggregation.
Tector, M, Salter, RD
Diedrich, G, Bangia, N, Pan, M, Cresswell, P
Harris, MR, Yu, YY, Kindle, CS, Hansen, TH, Solheim, JC
Ware, FE, Vassilakos, A, Peterson, PA, Jackson, MR, Lehrman, MA, Williams, DB
Danilczyk, UG, Cohen-Doyle, MF, Williams, DB
Stronge, VS, Saito, Y, Ihara, Y, Williams, DB
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