Alpha A-crystallin and alpha B-crystallin, newly identified interaction proteins of protease-activated receptor-2, rescue astrocytes from C2-ceramide- and staurosporine-induced cell death.

Abstract

Protease-activated receptor-2 (PAR-2) is a G protein-coupled receptor activated by trypsin and other trypsin-like serine proteases. The widely expressed PAR-2 is involved in inflammation response but the physiological/pathological roles of PAR-2 in the nervous system are still uncertain. In the present study, we report novel PAR-2 interaction proteins, alphaA-crystallin and alphaB-crystallin. These 20 kDa proteins have been implicated in neurodegenerative diseases like Alexander's disease, Creutzfeldt-Jacob disease, Alzheimer's disease, and Parkinson's disease. Results from yeast two-hybrid assay using the cytoplasmic C-tail of PAR-2 as bait suggested that alphaA-crystallin interacts with PAR-2. We further demonstrate the in vitro and cellular in vivo interaction of C-tail of PAR-2 as well as of full-length PAR-2 with alphaA(alphaB)-crystallins. We use pull-down, co-immunoprecipitation, and co-localization assays. Analysis of alphaA-crystallin deletion mutants showed that amino acids 120-130 and 136-154 of alphaA-crystallin are required for the interaction with PAR-2. Co-immunoprecipitation experiments ruled out an interaction of alphaA(alphaB)-crystallins with PAR-1, PAR-3, and PAR-4. This demonstrates that alphaA(alphaB)-crystallins are PAR-2-specific interaction proteins. Moreover, we investigated the functional role of PAR-2 and alpha-crystallins in astrocytes. Evidence is presented to show that PAR-2 activation and increased expression of alpha-crystallins reduced C2-ceramide- and staurosporine-induced cell death in astrocytes. Thus, both PAR-2 and alpha-crystallins are involved in cytoprotection in astrocytes.

• Authors: Rongyu Li, Tanuja Rohatgi, Theodor Hanck, Georg Reiser
• Journal: Journal of neurochemistry (J Neurochem) Vol. 110 Issue 5 Pg. 1433-44 (Sep 2009) ISSN: 1471-4159 [Electronic] England
• PMID: 19558454 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• N-acetylsphingosine
• Receptor, PAR-2
• alpha-Crystallin A Chain
• alpha-Crystallin B Chain
• Staurosporine
• Sphingosine

Topics

• Animals
• Astrocytes (drug effects, physiology)
• Cell Death (drug effects, physiology)
• Cell Line
• Cells, Cultured
• Humans
• Immunoprecipitation
• Insecta
• Protein Binding (drug effects, physiology)
• Rats
• Receptor, PAR-2 (metabolism)
• Sphingosine (analogs & derivatives, toxicity)
• Staurosporine (toxicity)
• alpha-Crystallin A Chain (metabolism, physiology)
• alpha-Crystallin B Chain (metabolism, physiology)