Caspase-2

Caspases are an extended family of cysteine proteases that play critical roles in apoptosis. Caspases are synthesized as precursors known as pro-caspases and these are converted into mature enzymes by apoptotic signals. Caspase-2 is an early effector in the apoptotic cascade and precedes the activation of caspase-3. It is generally found in the nucleus, but pro-caspase-2 may also be detected in mitochondrial and cytosolic fractions. Lymphoid organs display only weak caspase-2 expression, located in sinusal histiocytes and thymic epithelial cells. Extra-lymphoid caspase-2 reactivity is found in particular organs like the kidney. The caspase-2/caspase-3 cascade may be inhibited by the bcl-2 oncoprotein.

Image: Caspase-2 staining of Human Testis. Note intense nuclear staining of a proportion of the spermatogonia in the seminiferous tubules. Paraffin section.