Mining of caspase-7 substrates using a degradomic approach

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Caspases are crucial executioners of apoptosis.
• Caspase-3 and caspase-7 share substrate similarities but differ in cellular localization.
• This difference suggests unique substrates for each caspase.

Purpose of the Study:

• To identify novel substrates specifically cleaved by caspase-7.
• To understand the distinct roles of caspase-7 in apoptosis compared to caspase-3.

Main Methods:

• Utilized a degradomic approach using 2-DE on cell lysates from caspase-3-deficient MCF-7 cells.
• Incubated lysates with purified recombinant caspase-7 to identify proteolyzed proteins.
• Confirmed cleavage of candidate substrates, including Valosin-containing protein (VCP).

Main Results:

• Identified several proteins undergoing caspase-7-dependent proteolysis, forming the 'caspase-7 degradome'.
• The identified caspase-7 substrates were distinct from known caspase-3 substrates.
• Confirmed Valosin-containing protein (VCP) is cleaved by both caspase-7 and caspase-3 at specific sites (DELD307 and DELD580).

Conclusions:

• The degradomic analysis revealed distinct substrates for caspase-7, highlighting its unique functions in apoptosis.
• Further investigation of these substrates will elucidate caspase-7's specific roles in programmed cell death.
• Valosin-containing protein (VCP) is a validated substrate for both caspase-3 and caspase-7.