An ultrasensitive high-throughput electrochemiluminescence immunoassay for the Cdc42-associated protein tyrosine kinase ACK1

Highly sensitive electrogenerated chemiluminescence biosensor in profiling protein kinase activity and inhibition using gold nanoparticle as signal transduction probes

A novel electrogenerated chemiluminescence (ECL) biosensor using gold nanoparticles as signal transduction probes was described for the detection of kinase activity. The gold nanoparticles were specifically conjugated to the thiophosphate group after the phosphorylation process in the presence of adenosine 59-[c-thio] triphosphate (ATP-s) cosubstrate. Due to its good conductivity, large surface area, and excellent electroactivity to luminol oxidization, the gold nanoparticles extremely amplified the ECL signal of luminol, offering a highly sensitive ECL biosensor for kinase activity detection. Protein kinase A (PKA), an important enzyme in regulation of glycogen, sugar, and lipid metabolism in the human body, was used as a model to confirm the proof-of-concept strategy. The as-proposed biosensor presented high sensitivity, low detection limit of 0.07 U mL(-1), wide linear range (from 0.07 to 32 U mL(-1)), and excellent stability. Moreover, this biosensor can also be used for quantitative analysis of kinase inhibition. On the basis of the inhibitor concentration dependent ECL signal, the half-maximal inhibition value IC(50) of ellagic acid, a PKA inhibitor, was estimated, which was in agreement with those characterized with the conventional kinase assay. While nearly no ECL signal change can be observed in the presence of Tyrphostin AG1478, a tyrosine kinase inhibitor, but not PKA inhibitor, shows its excellent performance in kinase inhibitor screening. The simple and sensitive biosensor is promising in developing a high-through assay of in vitro kinase activity and inhibitor screening for clinic diagnostic and drug development.

Update on lymphocyte specific kinase inhibitors: a patent survey

IMPORTANCE OF THE FIELD

Lck (p56(lck) or lymphocyte specific kinase) is a cytoplasmic tyrosine kinase of the Src family expressed in T cells and natural killer (NK) cells. Genetic evidence from knockout mice and human mutations demonstrates that Lck kinase activity is critical for T cell receptor (TCR)-mediated signaling, leading to normal T-cell development and activation. Selective inhibition of Lck is expected to offer a new therapy for the treatment of T-cell-mediated autoimmune and inflammatory disorders and/or organ transplant rejection.

AREAS COVERED IN THIS REVIEW

This review covers the patents, patent applications and associated publications for small molecule kinase inhibitors of Lck since 2005 and attempts to place them in context from a structural point of view.

WHAT THE READER WILL GAIN

Readers will gain an overview of the structural classes and binding modes of Lck inhibitors, the major players in this area and an insight into the current state of the field.

TAKE HOME MESSAGE

The search for a potent and orally active inhibitor of Lck has been an intense area of research for a number of years. Despite tremendous efforts, the identification of a highly selective and potent Lck inhibitor suitable for use as an immunosuppressive agent remains elusive.