Kit for Specially Labeling, Extracting, and Purifying Endoplasmic Reticulum (ER)-Localized Proteins ER-Protein Capture Kit | Funakoshi

ER-Protein Capture Kit labels ER-associated proteins specifically and enables to isolate them by immunoprecipitation. This kit is a powerful tool for global analysis of various ER proteins.

The kit utilizes ERM (ER-localizable Reactive Molecule), a compound consisting of an ER-localizable green fluorescent dye (rhodol derivative) attached to a protein-reactive group.

• Step 1: Specific Labeling
  When added to live cells, ERM rapidly concentrates in the endoplasmic reticulum due to its specific dye properties, where it covalently labels ER proteins with a fluorescent tag via its reactive group.
• Step 2: Cell Lysis
  After the labeling reaction, cells are lysed to prepare a cell lysate.
• Step 3: Immunoprecipitation (IP)
  ERM-labeled ER proteins are selectively captured and recovered using the provided tag-capture antibody (anti-rhodol antibody).
• Step 4: Detection
  Since the recovered proteins retain the fluorescent tag, they can be separated by SDS-PAGE and detected directly via a fluorescence imager, or via CBB/silver staining.
• Step 5: Analysis
  After SDS-PAGE separation, proteins can be comprehensively analyzed by LC/MS proteomics or identified via Western Blotting (WB) using specific antibodies.

• Advantages over Conventional Methods
• Kit Components
• Reference Data
• Application Data
• Reference
• Webinar
• Product information

Advantages over Conventional Methods

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Kit Components

The kit includes two main components:

• A: ER-localizable Reactive Molecule (ERM)
  (Same product as ERseeing (#FDV-0038), which can also be purchased individually for live-cell ER imaging).
• B: Anti rhodol antibody (Purified Rabbit Polyclonal IgG)
  (Available as an individual item, Product Code: #FDV-0039B)
  Note: Lysis buffers for cell lysate preparation and Protein A/G resins required for immunoprecipitation are not included. Please prepare them separately.

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Reference Data

Excitation and Emission Spectra of ERM

Compatible with standard green fluorescence (FITC) observation conditions.

• Excitation Spectrum: Blue / Emission Spectrum: Red (Peak Ex/Em: 509 nm / 524 nm).

Validation of ER Specificity

Co-staining with various organelle markers confirmed high ER specificity:

• ER Markers: Exceptionally high co-localization (Pearson's correlation coefficient > 0.9).
• Lysosome & Mitochondria Markers: No co-localization observed.
• Golgi Marker: Partial co-localization observed. This indicates that some labeled proteins moved from the ER to the Golgi via the secretory pathway. (Co-localization with the Golgi decreases when an ER-to-Golgi transport inhibitor is added. For more detail, please see ☞ Reference.)

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Application Data

Comprehensive Proteomic Analysis of Recovered Proteins

HeLa cells were treated with 100 nM ERM, lysed, and immunoprecipitated using the tag-capture antibody and Protein A beads. Labeled proteins were separated by SDS-PAGE, and bands were analyzed via LC/MS after in-gel trypsin/Lys-C digestion.

• Results: A total of 146 proteins were identified.
• Breakdown: 63 proteins were confirmed ER-resident proteins. 73 proteins belonged to the plasma membrane, extracellular secretory pathway, or Golgi apparatus (which pass through the ER during synthesis).
• Accuracy: Approximately 93% of the detected proteins were ER-localized or passed through the secretory pathway, while only -7% (10 proteins) were unrelated to the ER.

Quantitative Evaluation of ER Protein Dynamics under ER Stress

ER stress-induced protein changes were analyzed using SILAC quantitative mass spectrometry.

• Cells grown in SILAC Heavy media were treated with Tunicamycin (an ER stress inducer) for 4 hours. Light media cells were left untreated.
• Both were labeled with 100 nM ERM for 1 hour, lysed, and mixed at a 1:1 ratio before immunoprecipitation and LC/MS.
• Results: Out of 87 quantifiable proteins detected, 6 proteins showed more than a 2-fold increase in ER localization following ER stress stimulation.

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Reference

• Fujisawa, A., et al., "Chemical Profiling of the Endoplasmic Reticulum Proteome Using Designer Labeling Reagents.", J. Am. Chem. Soc., 140, 17060-17070 (2018). [PMID: 30433779]

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Webinar

⇒Download here!

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Product information

[Date : July 16 2026 00:08]

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Detail	Product Name	Product Code	Supplier	Size	Price
	ER-Protein Capture Kit DatasheetThis may not be the latest data sheet.	FDV-0039	FNAFunakoshi Co.,Ltd.	1 kit	$600
	Contact	Description ER-Protein Capture Kit enables to purify ER associated proteins to evaluate various ER roles with easy procedures and no special equipment such as ultracentrifuge machine. Storage -20°C CAS Link ERseeing™ | Funakoshi

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[Date : July 16 2026 00:08]

ER-Protein Capture Kit

DatasheetThis may not be the latest data sheet.

• Product Code: FDV-0039
• Supplier: FNA
• Size: 1kit
• Price: $600

Description	ER-Protein Capture Kit enables to purify ER associated proteins to evaluate various ER roles with easy procedures and no special equipment such as ultracentrifuge machine.
Storage	-20°C	CAS
Link	ERseeing™ | Funakoshi

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Kit Components Sold Separately

[Date : July 16 2026 00:08]

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Detail	Product Name	Product Code	Supplier	Size	Price
	ERseeing, Endoplasmic Reticulum Green DatasheetThis may not be the latest data sheet.	FDV-0038	FNAFunakoshi Co.,Ltd.	10 nmol	$380
	Contact	Description ERseeing is irreversible ER labeling dye and suitable for long-term live imaging. Storage -20°C CAS Link ERseeing™ | Funakoshi ERseeing™(Endoplasmic Reticulum Green) in a minute
	ER-Protein Capture Kit component B <Anti-Rhodol antibody> DatasheetThis may not be the latest data sheet.	FDV-0039B	FNAFunakoshi Co.,Ltd.	200 µg	$350
	Contact	Description Component B of ER-Protein Capture Kit (#FDV-0039) is sold separately. Anti-Rhodol antibody. Concentration: 1 mg/mL. Formulation: 1 x PBS containing 50% glycerol. Host/Clonality: Rabbit polyclonal. Purification: Protein G purified Storage -20°C CAS Link

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• Detail display

[Date : July 16 2026 00:08]

ERseeing, Endoplasmic Reticulum Green

DatasheetThis may not be the latest data sheet.

• Product Code: FDV-0038
• Supplier: FNA
• Size: 10nmol
• Price: $380

Description	ERseeing is irreversible ER labeling dye and suitable for long-term live imaging.
Storage	-20°C	CAS
Link	ERseeing™ | Funakoshi ERseeing™(Endoplasmic Reticulum Green) in a minute

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ER-Protein Capture Kit component B <Anti-Rhodol antibody>

DatasheetThis may not be the latest data sheet.

• Product Code: FDV-0039B
• Supplier: FNA
• Size: 200µg
• Price: $350

Description	Component B of ER-Protein Capture Kit (#FDV-0039) is sold separately. Anti-Rhodol antibody. Concentration: 1 mg/mL. Formulation: 1 x PBS containing 50% glycerol. Host/Clonality: Rabbit polyclonal. Purification: Protein G purified
Storage	-20°C	CAS
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