Cysteinyl Aspartate Specific Proteinases 9 (CASPASE-9/MCH6/ICE-LAP6) ELISA Kit for Human

This gene encodes a member of the cysteine-aspartic acid protease (caspase) family. Sequential activation of caspases plays a central role in the execution-phase of cell apoptosis. Caspases exist as inactive proenzymes which undergo proteolytic processing at conserved aspartic residues to produce two subunits, large and small, that dimerize to form the active enzyme. This protein is processed by caspase APAF1; this step is thought to be one of the earliest in the caspase activation cascade. Alternative splicing results in two transcript variants which encode different isoforms. [provided by RefSeq]

Function: Involved in the activation cascade of caspases responsible for apoptosis execution. Binding of caspase-9 to Apaf-1 leads to activation of the protease which then cleaves and activates caspase-3. Proteolytically cleaves poly(ADP-ribose) polymerase (PARP).Isoform 2 lacks activity is an dominant-negative inhibitor of caspase-9.

Catalytic activity: Strict requirement for an Asp residue at position P1 and with a marked preference for His at position P2. It has a preferred cleavage sequence of Leu-Gly-His-Asp-|-Xaa.

Subunit structure: Heterotetramer that consists of two anti-parallel arranged heterodimers, each one formed by a 35 kDa (p35) and a 10 kDa (p10) subunit. Caspase-9 and APAF1 bind to each other via their respective NH2-terminal CED-3 homologous domains in the presence of cytochrome C and ATP. Interacts with the inhibitors BIRC2, BIRC4, BIRC5 and BIRC7. Interacts (inactive form) with EFHD2. Interacts with HAX1. Ref.13 Ref.15 Ref.16

Tissue specificity: Ubiquitous, with highest expression in the heart, moderate expression in liver, skeletal muscle, and pancreas. Low levels in all other tissues. Within the heart, specifically expressed in myocytes. Ref.13

Developmental stage: Expressed at low levels in fetal heart, at moderate levels in neonate heart, and at high levels in adult heart. Ref.13

Post-translational modification: Cleavages at Asp-315 by granzyme B and at Asp-330 by caspase-3 generate the two active subunits. Caspase-8 and -10 can also be involved in these processing events.

Sequence similarities: Belongs to the peptidase C14A family.Contains 1 CARD domain.