LRPAP in A549 Human Cell Line. LRPAP was detected in immersion fixed A549 human lung carcinoma cell line using Goat Anti-Human LRPAP Antigen Affinity-purified Polyclonal Antibody (Catalog # AF4296) at 10 µg/mL for 3 hours at room temperature. Cells were stained using the NorthernLights™ 557-conjugated Anti-Goat IgG Secondary Antibody (red; Catalog # NL001) and counterstained with DAPI (blue). Specific staining was localized to Golgi and endoplasmic reticula. View our protocol for Fluorescent ICC Staining of Cells on Coverslips.
Preparation and Storage
Reconstitute at 0.2 mg/mL in sterile PBS.
The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below. *Small pack size (SP) is shipped with polar packs. Upon receipt, store it immediately at -20 to -70 °C
Stability & Storage
Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
12 months from date of receipt, -20 to -70 °C as supplied.
1 month, 2 to 8 °C under sterile conditions after reconstitution.
6 months, -20 to -70 °C under sterile conditions after reconstitution.
LRPAP (LDL receptor-related protein-associated protein 1; also named RAP), is a ubiquitously expressed 39 kDa chaperone for LDL receptor family proteins (1, 2). Mature human LRPAP shares 77% amino acid sequence identity with mouse and rat LRPAP. It is organized into three domains of comparable length. Domains D2 and D3 interact with each other, while D1 is independent (3). The D1 domain contains a low affinity binding site for LRP, and the associated D2 and D3 domains bind LRP with high affinity (4). The majority of LRPAP is localized in the endoplasmic reticulum and Golgi (5). LRPAP prevents the premature interaction of LRP, LRP2/megalin, and VLDLR with their coexpressed ligands, thereby promoting proper receptor folding and export from the ER (6‑8). Protonation of conserved histidine residues within the D3 domain induces the separation of LRPAP and LRP in the relatively acidic Golgi (9). LRPAP, which contains a C-terminal HNEL motif, can then recycle to the ER (9). A minor amount of LRPAP remains associated with LRP and can modulate receptor activity on the cell surface (5). Exogenously applied LRPAP competitively inhibits LDL receptor family binding and uptake of activated alpha 2-macroglobulin, apoB100- or apoE-enriched LDL and VLDL particles, cholesteryl esters, and complexes of PAI-1 with either tPA or uPA (10‑14).
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Low Density Lipoprotein-Related Protein-associated Protein
Entrez Gene IDs:
4043 (Human); 16976 (Mouse); 116565 (Rat)
A2MRAP; A2MRAPMRAP; A2RAP; alpha-2-macroglobulin receptor-associated protein 1; alpha-2-macroglobulin receptor-associated protein; alpha-2-MRAP; HBP44; lipoprotein receptor associated protein; low density lipoprotein receptor-related protein associated protein 1; Low density lipoprotein receptor-related protein-associated protein 1; low density lipoprotein-related protein-associated protein 1(alpha-2-macroglobulin receptor-associated protein 1); LRPAP; LRPAP1; MGC138272; RAP
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