serine protease HTRA2, mitochondrial; high temperature requirement protein A2; HtrA2; Omi stress-regulated endoprotease; serine protease 25; serine proteinase OMI (HTRA2, OMI, PRSS25)

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Function

serine protease
proteolytic activity against a non-specific substrate, beta-casein
promotes or induces cell death either by direct binding to & inhibition of IAP protein/BIRC protein family, leading to an increase in caspase activity, or by a BIRC inhibition- independent, caspase-independent & serine protease activity
cleaves THAP5 & promotes its degradation during apoptosis
isoform 2 seems to be proteolytically inactive
cleavage of non-polar aliphatic amino-acids at the P1 position, with a preference for Val, Ile & Met
at the P2 & P3 positions, Arg is selected most strongly with a secondary preference for other hydrophilic residues
autoproteolytically activated
interacts with MXI2
interacts with THAP5 under apoptotic conditions
the mature protein, but not the precursor, binds to BIRC2, BIRC3 & XIAP

mitochondrial intermembrane space
mitochondrial membrane
single-pass membrane protein (putative)
predominantly present in mitochondrial intermembrane space
released into the cytosol following apoptotic stimuli, such as UV treatment, & stimulation of mitochondria with caspase-8 truncated BID/tBID