Part of Thermo Fisher Scientific




Low-density lipoprotein receptor-related protein 2

See alternative names Megalin,
Glycoprotein 330

Uniprot Function Description

Multiligand endocytic receptor (By similarity). Acts together with CUBN to mediate endocytosis of high-density lipoproteins (By similarity). Mediates receptor-mediated uptake of polybasic drugs such as aprotinin, aminoglycosides and polymyxin B (By similarity). In the kidney, mediates the tubular uptake and clearance of leptin (By similarity). Also mediates transport of leptin across the blood-brain barrier through endocytosis at the choroid plexus epithelium (By similarity). Endocytosis of leptin in neuronal cells is required for hypothalamic leptin signaling and leptin-mediated regulation of feeding and body weight (By similarity). Mediates endocytosis and subsequent lysosomal degradation of CST3 in kidney proximal tubule cells (By similarity). Mediates renal uptake of 25-hydroxyvitamin D3 in complex with the vitamin D3 transporter GC/DBP (By similarity). Mediates renal uptake of metallothionein-bound heavy metals (PubMed:15126248). Together with CUBN, mediates renal reabsorption of myoglobin (By similarity). Mediates renal uptake and subsequent lysosomal degradation of APOM (By similarity). Plays a role in kidney selenium homeostasis by mediating renal endocytosis of selenoprotein SEPP1 (By similarity). Mediates renal uptake of the antiapoptotic protein BIRC5/survivin which may be important for functional integrity of the kidney (PubMed:23825075). Mediates renal uptake of matrix metalloproteinase MMP2 in complex with metalloproteinase inhibitor TIMP1 (By similarity). Mediates endocytosis of Sonic hedgehog protein N-product (ShhN), the active product of SHH (By similarity). Also mediates ShhN transcytosis (By similarity). In the embryonic neuroepithelium, mediates endocytic uptake and degradation of BMP4, is required for correct SHH localization in the ventral neural tube and plays a role in patterning of the ventral telencephalon (By similarity). Required at the onset of neurulation to sequester SHH on the apical surface of neuroepithelial cells of the rostral diencephalon ventral midline and to control PTCH1-dependent uptake and intracellular trafficking of SHH (By similarity). During neurulation, required in neuroepithelial cells for uptake of folate bound to the folate receptor FOLR1 which is necessary for neural tube closure (By similarity). In the adult brain, negatively regulates BMP signaling in the subependymal zone which enables neurogenesis to proceed (By similarity). In astrocytes, mediates endocytosis of ALB which is required for the synthesis of the neurotrophic factor oleic acid (By similarity). Involved in neurite branching (By similarity). During optic nerve development, required for SHH-mediated migration and proliferation of oligodendrocyte precursor cells (By similarity). Mediates endocytic uptake and clearance of SHH in the retinal margin which protects retinal progenitor cells from mitogenic stimuli and keeps them quiescent (By similarity). Plays a role in reproductive organ development by mediating uptake in reproductive tissues of androgen and estrogen bound to the sex hormone binding protein SHBG (By similarity). Mediates endocytosis of angiotensin-2 (By similarity). Also mediates endocytosis of angiotensis 1-7 (By similarity). Binds to the complex composed of beta-amyloid protein 40 and CLU/APOJ and mediates its endocytosis and lysosomal degradation (By similarity). Required for embryonic heart development (By similarity). Required for normal hearing, possibly through interaction with estrogen in the inner ear (By similarity).

Sample type

Human EDTA plasma and serum are the recommended sample types. Human citrate plasma and heparin plasma are also accepted. For other samples types e.g cerebrospinal fluid, (CSF), tissue or cell lysates please we recommend Olink Target 96 panels. Please note that protein expression levels are expected to vary in different sample types and certain assays may be affected by interfering substances such as hemolysate.


Precision (repeatability) is calculated from linearized NPX values over LOD.

Within run precision Coefficient of Variation (CV)
Between run precision Coefficient of Variation (CV)

Analytical measuring range

The technical data reported below refers to the measured value in the in vitro validation assays run using known concentrations of recombinant antigen. Please note that these figures are for reference only and CANNOT be used to convert NPX values to absolute concentrations for proteins measured in plasma or serum samples.

LOD (pg/mL)
LLOQ (pg/mL)
ULOQ (pg/mL)
Hook (pg/mL)
Range (logs)

Dilution factor

For optimal assay readout, Olink Explore is run using different dilutions of the original samples (undiluted, 1:10, 1:100 or 1:1000). The dilution factor for this assay is noted below and should be taken into account when estimating the appropriate addressable biological concentration of the protein based on the in vitro validation data.

Dilution factor

Sensitivity plot

The calibrator curve shown below visualizes the analytical measuring range data based on in vitro measurement of recombinant antigen. Please note that this is shown for reference only and CANNOT be used to convert NPX values to absolute concentrations for proteins measured in plasma or serum samples. The vertical dotted lines represent LLOQ and ULOQ respectively, and the horizontal line indicates the LOD.


Sample distribution plot

The plot below shows the levels of protein measured in a number of commercial plasma samples. Healthy subjects are shown in blue and samples obtained from patients with a range of diseases are shown in red. The latter include inflammatory, cardiovascular, autoimmune & neurological diseases, as well as cancer. The data is shown to give a general idea of the sort of data range to expect, but cannot cover all potential levels that may be seen in clinical samples.

1614121086420−2−4NPXControl SamplesDisease Samples