REGIONAL CALPAIN AND CASPASE-3 PROTEOLYSIS OF ALPHA-SPECTRIN AFTER TRAUMATIC BRAIN INJURY

ACTIVITY Of calpains and caspase-3 inferred from proteolysis of the cy toskeletal protein cx-spectrin into signature spectrin breakdown produ cts (SBDPs) was used to provide the first systematic and simultaneous comparison of changes in activity of these two families of cysteine pr oteases after traumatic brain injury (TBI) in rats. Distinct regional and temporal patterns of calpain/caspase-3 processing of alpha-spectri n were observed in brain regions ipsilateral to the site of injury aft er TBI, including large increases of 145 kDa calpain-mediated SBDP in cortex (up to 30-fold), and enduring increases (up to 2 weeks) of 145 kDa SBDP in hippocampus and thalamus. By contrast, 120kDa caspase-3-me diated SBDP was absent in cortex and showed up to a 2-fold increase in hippocampus and striatum at early (hours) after TBI. Future studies w ill clarify the pathological significance of large regional difference s in activation of calpain and caspase-3 proteases after TBI. NeuroRep ort 9: 2437-2442 (C) 1998 Rapid Science Ltd.