Related Experiment Video
Updated: Aug 29, 2026

Assessing Cellular Target Engagement by SHP2 (PTPN11) Phosphatase Inhibitors
Published on: July 17, 2020
Properties of the co-chaperone protein p23 erroneously attributed to ALG-2 (apoptosis-linked gene 2)
Jens Mollerup1, Thomas N Krogh, Per F Nielsen
1Department of Molecular Cell Biology, Institute of Molecular Biology, University of Copenhagen, Øster Farimagsgade 2A, 1353 Copenhagen K, Denmark. jmollerup@my.molbio.ku.dk
Abstract:
A commercial antibody (clone 22) directed against the apoptosis-linked gene 2 (alg2, pdcd6) encoded protein has been used by several groups. Up-regulated expression of the antigen was observed in primary tumours and in metastatic tissue and also during rat brain ischemia. Furthermore, antigen down-regulation was found in human atherosclerotic plaques. Recently, we found that the clone 22 antibody does not recognise ALG-2. In the present study the antigen of the clone 22 antibody was identified as the heat shock protein 90 (HSP90) co-chaperone protein p23, identical to the cytosolic prostaglandin E2 synthase, by immunoprecipitation followed by tryptic in-gel digests and mass spectrometry of the purified peptides. Moreover, the heterogeneous ribonuclear protein A2/B1 was found to be a part of the p23 co-immunoprecipitated protein complex.
Related Concept Videos
Abnormal Proliferation
Covalently Linked Protein Regulators
These groups modify specific amino acids in a protein.
Molecular Chaperones and Protein Folding
The...
The Intrinsic Apoptotic Pathway
Negative Regulator Molecules
Allosteric Proteins-ATCase
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...

