Proximity ligation assay to study protein–protein interactions of proteins on two different cells
Rushikesh Sable,
Nithya Jambunathan,
Sitanshu Singh,
Sandeep Pallerla,
Konstantin G Kousoulas,
Seetharama Jois
Affiliations
Rushikesh Sable
1Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, LA 71201, USA
Nithya Jambunathan
2Division of Biotechnology & Molecular Medicine & Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
Sitanshu Singh
1Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, LA 71201, USA
Sandeep Pallerla
1Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, LA 71201, USA
Konstantin G Kousoulas
2Division of Biotechnology & Molecular Medicine & Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
Seetharama Jois
1Basic Pharmaceutical Sciences, School of Pharmacy, University of Louisiana at Monroe, LA 71201, USA
Protein–protein interactions (PPI) by homo-, hetero- or oligo-merization in the cellular environment regulate cellular processes. PPI can be inhibited by antibodies, small molecules or peptides, and this inhibition has therapeutic value. A recently developed method, the proximity ligation assay (PLA), provides detection of PPI in the cellular environment. However, most applications using this assay are for proteins expressed in the same cell. We employ PLA for the first time to study PPI of cell surface proteins on two different cells. Inhibition of PPI using a peptide inhibitor is also quantified using this assay; PLA is used to detect PPI of CD2 and CD58 between Jurkat cells (T cells) and human fibroblast-like synoviocyte-rheumatoid arthritis cells that are important in the immune response in the autoimmune disease rheumatoid arthritis. This assay provides direct evidence of inhibition of PPI of two proteins on different cell surfaces.
