Mannose Receptor（MRC1）

Mannose Receptor protein structure

Image 1: Mannose Receptor protein structure.

Mannose Receptor Introduction

Protein Function

The Mannose Receptor, also known as CD206, is a heavily glycosylated type I transmembrane protein expressed by populations of dendritic cells, macrophages, and nonvascular endothelium.
The Mannose Receptor mediates the internalization of soluble and particulate carbohydrate structures, thereby participating in innate immunity.
It mediates the endocytosis of glycoproteins by macrophages, Binds both sulfated and non-sulfated polysaccharide chains.
The Mannose Receptor acts as phagocytic receptor for bacteria, fungi and other pathogens, or Dengue virus envelope protein E.

Protein Expression

Highly expressed in lung and lymphoid tissues.

Protein Localization

Mannose Receptor protein localizes to the cell membrane and endosome membrane.

Mannose Receptor ICC experimental results using Anti-Mannose Receptor antibody [EPR25215-277] (ab300621)

Figure 2: Mannose Receptor ICC experimental results using Anti-Mannose Receptor antibody [EPR25215-277] (ab300621). Untreated: Raw 264.7 cells. Treated: Raw 264.7 cells treated with IL-4 (40 ng/ml) for 4 days, then IL-10 (40 ng/ml) for another 4 days. Green: Mannose Receptor. Red: alpha Tubulin. Blue: DAPI.

Isoforms & Post-Translational Modifications

Human (P22897): Isoform 1: Predicted molecular weight of 166 kDa.
Isoform 2: Predicted molecular weight of 57 kDa.
Mouse (Q61830): Predicted molecular weight of 165 kDa.
Rat (D3ZD31): Predicted molecular weight of 165 kDa.
Mannose Receptor undergoes disulfide bonding and glycosylation modifications.

WB Experiment Tips

Precautions

Mannose Receptor (CD206) is predominantly expressed in macrophages and dendritic cells, and also in endothelial cells of lymphatic, hepatic, and splenic tissues, mesangial cells of kidneys, smooth muscle cells of trachea, and retinal pigment epithelium. It is recommended to choose tissues with higher expression levels, such as lung, as positive controls.
Mannose Receptor (CD206) is a membrane-bound protein predicted to be approximately 166 kDa. Boiling samples may cause protein aggregation. If no signal is observed, it is suggested to avoid boiling the samples after preparation.
Expression of Mannose Receptor in the brain peaks in the first week of life and then sharply declines, maintaining low levels throughout adulthood. Therefore, it is difficult to detect signals in normal whole brain lysates.
Mannose Receptor also exists in a soluble form, soluble CD206, which can be found in culture media of human dendritic cells, human macrophages, and mouse macrophages, as well as in human and mouse serum. Studies have shown that soluble forms of CD206 have smaller molecular weights compared to membrane-bound forms.
Mannose Receptor undergoes post-translational modifications, such as glycosylation, which may result in a larger observed molecular weight than predicted.
During inflammatory responses, IL-4 and IL-13 stimulate upregulation of Mannose Receptor (CD206) expression. For certain cells like RAW264.7, treatment with IL-4 and IL-10 increases CD206 expression, making stimulation beneficial for addressing issues such as weak or absent signals in WB experiments. (Refer to positive controls for guidance)

Positive Controls

Lung tissue lysate.

Negative Controls (No or Weak Expression)

Mouse: Brain tissue lysate, RAW 264.7 whole cell lysate.
Rat: Brain tissue lysate.

Example Results

WB - Anti-Mannose Receptor antibody [EPR25215-277] (ab300621)

Figure 3: WB - Anti-Mannose Receptor antibody [EPR25215-277] (ab300621)

Lane 1: Mouse lung tissue lysate
Lane 2: Mouse liver tissue lysate
Lane 3: Mouse brain tissue lysate
Lane 4: Raw264.7 whole cell lysate
Lane 5: Raw264.7 treated with 20 ng/ml IL-4 and 10 µM Dexamethasone for 18 hours whole cell lysate
Lane 6: Rat lung tissue lysate
Lane 7: Rat liver tissue lysate
Lane 8: Rat brain tissue lysate

Loading: 20 µg per lane

Predicted Band Size: 166 kDa
Observed Band Size: 200 kDa

Exposure Time: 3 minutes
Blocking and Antibody Dilution: 5% NFDM/TBST

Key control points

In the experiment, in addition to paying attention to routine issues, special attention should be paid to the following key control points:

Sample preparation:

Add a protease inhibitor cocktail to prevent degradation of target proteins.
Keep samples on ice throughout the entire sample preparation process.
Determine the total protein concentration of the sample using Bradford analysis, Lowry analysis, or BCA analysis.
If there is no signal or weak signal after boiling the sample, it is strongly recommended not to boil the sample to prevent protein aggregation.

Electrophoresis:

Use freshly prepared lysis buffer.
Load at least 20μg total protein for electrophoresis.
For target proteins with larger molecular weights (e.g., >100 kDa), it is recommended to use an 8% separating gel for electrophoresis.

Transfer:

Add SDS to the transfer buffer to a final concentration of 0.1%.
After activating the PVDF membrane, thoroughly wash it to completely remove any residual methanol.
It is recommended to use 10% methanol concentration in the transfer buffer.
It is recommended to stain the membrane with Ponceau S after the transfer to confirm the success of the transfer.