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ZO-1 Polyclonal antibody

ZO-1 Polyclonal Antibody for WB, IP, IF, FC, IHC, ELISA

Host / Isotype

Rabbit / IgG


human, canine, mouse, rat, hamster and More (5)





Cat no : 21773-1-AP


Tight junction protein 1, Tight junction protein ZO 1, TJP1, ZO 1, ZO1, ZO-1, Zona occludens protein 1, Zonula occludens protein 1

Tested Applications

Positive WB detected inA549 cells, HEK-293 cells, COLO 320 cells, HT-29 cells, HUVEC cells, HepG2 cells, mouse brain tissue, rat brain tissue, MCF-7 cells, Caco-2 cells, HeLa cells, K-562 cells
Positive IP detected inHEK-293 cells
Positive IHC detected inmouse kidney tissue
Note: suggested antigen retrieval with TE buffer pH 9.0; (*) Alternatively, antigen retrieval may be performed with citrate buffer pH 6.0
Positive IF detected inMCF-7 cells, MDCK cells, HUVEC cells
Positive FC detected inMCF-7 cells

Recommended dilution

Western Blot (WB)WB : 1:5000-1:50000
Immunoprecipitation (IP)IP : 0.5-4.0 ug for 1.0-3.0 mg of total protein lysate
Immunohistochemistry (IHC)IHC : 1:1000-1:4000
Immunofluorescence (IF)IF : 1:100-1:2000
Flow Cytometry (FC)FC : 0.20 ug per 10^6 cells in a 100 µl suspension
It is recommended that this reagent should be titrated in each testing system to obtain optimal results.
Sample-dependent, Check data in validation data gallery.

Product Information

21773-1-AP targets ZO-1 in WB, IP, IF, FC, RIP, IHC, ELISA applications and shows reactivity with human, canine, mouse, rat, hamster samples.

Tested Reactivity human, canine, mouse, rat, hamster
Cited Reactivityhuman, mouse, rat, goat, chicken, rabbit, pig, canine, bovine
Host / Isotype Rabbit / IgG
Class Polyclonal
Type Antibody
Immunogen ZO-1 fusion protein Ag16454
Full Name tight junction protein 1 (zona occludens 1)
Calculated Molecular Weight 1748 aa, 195 kDa
Observed Molecular Weight 230 kDa
GenBank Accession NumberBC111712
Gene Symbol TJP1
Gene ID (NCBI) 7082
Conjugate Unconjugated
Form Liquid
Purification MethodAntigen affinity purification
Storage Buffer PBS with 0.02% sodium azide and 50% glycerol pH 7.3.
Storage ConditionsStore at -20°C. Stable for one year after shipment. Aliquoting is unnecessary for -20oC storage. 20ul sizes contain 0.1% BSA.

Background Information

What is the function of ZO-1?

Zona Occludens 1 (ZO-1) is a tight junction (TJ) protein found in complexes at cell-cell contacts. The role of ZO-1 is to recruit other TJ proteins.1,2 The resulting TJ complexes regulate paracellular flow, contribute to apical-basal polarity, and are part of signaling pathways for proliferation and differentiation.3 This protein is useful for highlighting cell-cell contacts both in cultured cells and in tissue samples, outlining cell membranes and specific structures.


Where is ZO-1 expressed?

The protein is localized to the cytoplasmic membrane in most types of cells, particularly where a barrier function is essential. It is common in endothelial cells,4 which line the internal surface of blood and lymph vessels, and in epithelial cells,5 which form the outer barrier of organs.

ZO-1 is expressed in many tissues including the intestine, kidney, liver, and skeletal muscle cells.


What proteins does ZO-1 interact with?

The molecular weight of ZO-1 is 220kDa6 and it contains multiple distinct protein domains that allow bind to other junctional proteins at the cytoplasmic membrane. The N-terminal of ZO-1 can dimerize with other ZO proteins and bind directly to other TJ proteins including claudins, connexions, and JAMs,7-10 which allows it to assemble TJ complexes. The C-terminal can interact with actin and cortactin, anchoring the TJ complexes to the cytoskeleton.8,11 This suggests that ZO-1 forms a link between the outer cell-cell contacts and the inner actin.


1.     McNeil, E., Capaldo, C. T. & Macara, I. G. Zonula occludens-1 function in the assembly of tight junctions in Madin-Darby canine kidney epithelial cells. Mol. Biol. Cell 17, 1922-32 (2006).

2.     Kratzer, I. et al. Complexity and developmental changes in the expression pattern of claudins at the blood-CSF barrier. Histochem. Cell Biol. (2012). doi:10.1007/s00418-012-1001-9

3.     Guillemot, L., Paschoud, S., Pulimeno, P., Foglia, A. & Citi, S. The cytoplasmic plaque of tight junctions: A scaffolding and signalling center. Biochim. Biophys. Acta - Biomembr. 1778, 601-613 (2008).

4.     Tornavaca, O. et al. ZO-1 controls endothelial adherens junctions, cell-cell tension, angiogenesis, and barrier formation. J. Cell Biol. 208, 821-38 (2015).

5.     Umeda, K. et al. Establishment and characterization of cultured epithelial cells lacking expression of ZO-1. J. Biol. Chem. 279, 44785-94 (2004).

6.     Stevenson, B. R. Identification of ZO-1: a high molecular weight polypeptide associated with the tight junction (zonula occludens) in a variety of epithelia. J. Cell Biol. 103, 755-766 (1986).

7.     Itoh, M. et al. Direct Binding of Three Tight Junction-Associated Maguks, Zo-1, Zo-2, and Zo-3, with the Cooh Termini of Claudins. J. Cell Biol. 147, 1351-1363 (1999).

8.     Fanning, A. S., Jameson, B. J., Jesaitis, L. A. & Anderson, J. M. The Tight Junction Protein ZO-1 Establishes a Link between the Transmembrane Protein Occludin and the Actin Cytoskeleton. J. Biol. Chem. 273, 29745-29753 (1998).

9.     Kausalya, P. J., Reichert, M. & Hunziker, W. Connexin45 directly binds to ZO-1 and localizes to the tight junction region in epithelial MDCK cells. FEBS Lett. 505, 92-96 (2001).

10. Itoh, M. et al. Junctional adhesion molecule (JAM) binds to PAR-3. J. Cell Biol. 154, 491-498 (2001).

11. Itoh, M., Nagafuchi, A., Moroi, S. & Tsukita, S. Involvement of ZO-1 in Cadherin-based Cell Adhesion through Its Direct Binding to α Catenin and Actin Filaments. J. Cell Biol. 138, 181-192 (1997).  


Product Specific Protocols
WB protocol for ZO-1 antibody 21773-1-APDownload protocol
IHC protocol for ZO-1 antibody 21773-1-APDownload protocol
IF protocol for ZO-1 antibody 21773-1-APDownload protocol
IP protocol for ZO-1 antibody 21773-1-APDownload protocol
Standard Protocols
Click here to view our Standard Protocols



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The reviews below have been submitted by verified Proteintech customers who received an incentive forproviding their feedback.


Sarah (Verified Customer) (03-20-2024)

The antibody works perfect.

  • Applications: Immunofluorescence
  • Primary Antibody Dilution: 1:1000
  • Cell Tissue Type: Cryosections intestine
ZO-1 Antibody Immunofluorescence validation (1:1000 dilution) in Cryosections intestine (Cat no:21773-1-AP)

Xie (Verified Customer) (10-26-2021)

Efficient Labelling from proteintech ZO1 Antibody

  • Applications: Immunofluorescence
  • Primary Antibody Dilution: 1:150
  • Cell Tissue Type: CaCo-2 cell line
ZO-1 Antibody Immunofluorescence validation (1:150 dilution) in CaCo-2 cell line (Cat no:21773-1-AP)

Samuel (Verified Customer) (08-06-2021)

Clean and strong band at 220-230 kDa in WB (reducing and denaturing conditions). I used the antibody at a 1:2500 dilution in 5% milk, incubation overnight at 4 degrees Celsius. 30ug loaded per sample.

  • Applications: Western Blot
  • Primary Antibody Dilution: 1/2500
  • Cell Tissue Type: SH-SY5Y, HEPG2, HEK293. 30ug each
ZO-1 Antibody Western Blot validation (1/2500 dilution) in SH-SY5Y, HEPG2, HEK293. 30ug each (Cat no:21773-1-AP)