Characterization of mitochondrial calpain-5

Calpain, a Ca2+-dependent cysteine protease, plays significant role in gene expression, signal transduction, and apoptosis. Mutations human calpain-5 cause autosomal dominant neovascular inflammatory vitreoretinopathy the inhibition of activity may constitute an effective therapeutic strategy for this condition. Although is ubiquitously expressed mammalian tissues was recently found to be present mitochondria as well cytosol, its physiological function enzymological properties require further elucidation. The objective current study determine characteristics mitochondrial porcine retinas, HeLa cells, C57BL/6J mice using subcellular fractionation. We that proteolyzed/autolyzed at low Ca2+ concentrations isolated from retinas by thapsigargin-induced endoplasmic reticulum (ER) stress cells. Further, calpain-5, opposed cytosolic activated during early stages ER mice. These results showed vitro response vivo. provides new insights into novel calpain system includes responses phases stress. activation treatment low-molecular-weight compounds have potential diseases related stress, including neurodegenerative diseases, metabolic syndromes, diabetes, cancer.