Proximity Ligation Assay

The in situ proximity ligation assay is a powerful technology capable of detecting single protein events such as protein protein interactions (e.g. protein dimerization) and modifications (e.g. protein phosphorylation) in tissue and cell samples prepared for microscopy. Each detected signal is visualized as an individual fluorescent dot, these signals can be quantified (counted) and assigned to a specific subcellular location based on microscopy images. This revolutionary technique enables unprecedented specificity and sensitivity of protein detection and quantification for high performance immunofluorescence and immunohistochemistry applications. Leveraging on Abnova's manufacturing capability and growing collection of 50,000+ antibodies, hundreds of target specific and validated assays are being developed in cells and tissue samples.

Principle of Proximity Ligation Assay


1.	Incubate with target primary antibodies from two different species	2.	Add probes	3.	Hybridize connector oligos


4.	Ligation to form a complete DNA circle	5.	Rolling circle amplification	6.	Add fluorescent probes to reveal protein protein interaction

Protein Protein Interaction Studies

Product Name: FLT1 & CTNNB1 Protein Protein Interaction Antibody Pair Catalog # : DI0010	Product Name: TRAF2 & ACTG1 Protein Protein Interaction Antibody Pair Catalog # : DI0041	Product Name: SNCA & BAX Protein Protein Interaction Antibody Pair Catalog # : DI0070

Huh7 cells were stained with anti-FLT1 rabbit purified polyclonal antibody and anti-CTNNB1 mouse monoclonal antibody. Each red dot represents the detection of protein-protein interaction complex.	HeLa cells were stained with anti-TRAF2 rabbit purified polyclonal antibody and anti-ACTG1 mouse monoclonal antibody. Each red dot represents the detection of protein-protein interaction complex.	HeLa cells were stained with anti-SNCA rabbit purified polyclonal antibody and anti-BAX mouse monoclonal antibody. Each red dot represents the detection of protein-protein interaction complex.

Protein Phosphorylation Studies

Product Name: Phospho-DNMT1(Y399) & DNMT1 Dual Recognition Antibody Pair Catalog # : DP0002	Product Name: Phospho-PDGFRB(Y579) & PDGFRB Dual Recognition Antibody Pair Catalog # : DP0004	Product Name: Phospho-RAF1(S259) & RAF1 Dual Recognition Antibody Pair Catalog # : DP0003

The phosphorylation of DNMT1 protein on Y399 in HeLa cell. Each red dot represents a phosphorylated protein.	The phosphorylation of PDGFRB protein on Y579 in BJ hTert cell stimulated with PDGF-BB. Each red dot represents a phosphorylated protein.	The phosphorylation of RAF1 protein on S259 in HeLa cell. Each red dot represents a phosphorylated protein.

*The images were analyzed using an optimized freeware (BlobFinder) download from The Centre for Image Analysis at Uppsala University.

Publication Reference

In situ detection of phosphorylated platelet-derived growth factor receptor beta using a generalized proximity ligation method.

Jarvius M, Paulsson J, Weibrecht I et al. Mol Cell Proteomics. 2007 Sep;6(9):1500-9. Epub 2007 Jun 12.

Direct observation of individual endogenous protein complexes in situ by proximity ligation.

Soderberg O, Gullberg M, Jarvius M et al. Nat Methods. 2006 Dec;3(12):995-1000. Epub 2006 Oct 29.

Cytokine detection by antibody-based proximity ligation.

Gullberg M, Gustafsdottir SM, Schallmeiner E et al. Proc Natl Acad Sci U S A. 2004 Jun 1;101(22):8420-4. Epub 2004 May 21.

Protein detection using proximity-dependent DNA ligation assays.

Fredriksson S, Gullberg M, Jarvius J et al. Nat Biotechnol. 2002 May;20(5):473-7.