Calnexin Monoclonal Antibody (AF18), Invitrogen™

Description

• MA3-027 detects calnexin from human and mouse tissues
• MA3-027 has been successfully used in Western blot, immunocytochemistry, immunofluorescence and immunoprecipitation protocols
• By Western blot, this antibody detects calnexin in human liver, skin, adrenal gland, heart, colon, testes and ovary extracts
• This antibody is not recommended for human kidney or mouse liver lysates in Western blot applications
• The predicted molecular weight of this antibody is ∽67kDa; however, it may run on SDS-PAGE as an ∽90kDA protein
• This is due mainly to negative charges at the C-terminus of the protein, which effects the SDS binding to the molecules and consequently its SDS-PAGE mobility
• Immunocytochemical staining of calnexin in Huh-7 cells with MA3-027 yields a pattern consistent with specific endoplasmic reticulum staining
• The MA3-027 antigen is Focus human hepatoma cell lysate
• Calnexin, also referred to as IP90, p88 and p90, is an approximately 90 kDa integral membrane protein of the endoplasmic reticulum (ER)
• Many resident ER proteins act as molecular chaperones and participate in the proper folding of polypeptides and their assembly into multisubunit proteins
• Studies indicate that calnexin associates with the major histocompatibility complex (MHC) class I heavy chains, partial complexes of the T cell receptor and B cell membrane immunoglobulin, but not with completed receptor complexes
• It has been shown that calnexin is a chaperone that retains incompletely or improperly folded proteins in the ER
• The sequence Lys-Asp-Glu-Leu (KDEL) or a closely related sequence, is present at the carboxy-terminus of soluble ER resident proteins such as GRP78 and GRP94 and protein disulfide isomerase
• Integral membrane ER resident proteins, like calnexin, often lack this KDEL sequence but contain positively charged cytosolic residues that ensure ER retention
• Calnexin contains a large ER luminal domain (461 amino acids), a transmembrane segment (22 amino acids), and a cytoplasmic tail (89 amino acids).