The Caspases, and Their Role in Apoptosis

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The Caspases, and Their Role in Apoptosis

• Caspases are-
• Cysteine proteases
• Asparteases, in that they cleave after
  aspartase residues
• Different caspases tend to recognise different
  motifs

Activation
Some caspases have long prodomains that interact
with other proteins Examples of these are
caspases 2,8 10. Caspases 2 binds to another
molecule RAIDD that may play a role in its
activation. Caspase 8 binds to FADD which is
involved in its activation via the FAS receptor.
Caspase 9 binds to APAF1, which is associated
with its activation. It appears that long
prodomain caspases can be auto activated when
brought to high local concentration by binding to
suitable partners in the complexes
Multiple caspases are present in living cells,
but exist as proforms (zymogens). During
apoptotic death zymogens are activated. One major
mechanism is that the inactive zymogens become
cleaved and are then in their active enzyme form.
This full dissertation can be found at the URL
below. The site was designed using Macromedia
Flash 5. The site also contains animated diagrams
and running documentary. The site explains the
role of all the caspase enzymes and in
particular, their role in programmed cell death.
A CD-Rom is also contained within the project and
explains in-depth the processes and pathways
used by these proteolytic enzymes
http//homepage.ntlworld.com/markhewitson/ntlup.sw
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