Structural highlights
Function
[CASP3_HUMAN] Involved in the activation cascade of caspases responsible for apoptosis execution. At the onset of apoptosis it proteolytically cleaves poly(ADP-ribose) polymerase (PARP) at a '216-Asp-|-Gly-217' bond. Cleaves and activates sterol regulatory element binding proteins (SREBPs) between the basic helix-loop-helix leucine zipper domain and the membrane attachment domain. Cleaves and activates caspase-6, -7 and -9. Involved in the cleavage of huntingtin. Triggers cell adhesion in sympathetic neurons through RET cleavage.[1] [2]
Publication Abstract from PubMed
Interactions between loops 2, 2' and 4, known as the loop bundle, stabilize the active site of caspase-3. Loop 4 (L4) is of particular interest due to its location between the active site and the dimer interface. We have disrupted a salt bridge between K242 and E246 at the base of L4 to determine its role in overall conformational stability and in maintaining the active site environment. Stability measurements show that only the K242A single mutant decreases stability of the dimer, whereas both single mutants and the double mutant demonstrate much lower activity compared to wild-type caspase-3. Structural studies of the caspase-3 variants show the involvement of K242 in hydrophobic interactions that stabilize helix 5, near the dimer interface, and the role of E246 appears to be to neutralize the positive charge of K242 within the hydrophobic cluster. Overall, the results suggest E246 and K242 are important in procaspase-3 for their interaction with neighboring residues, not with one another. Conversely, formation of the K242-E246 salt bridge in caspase-3 is needed for an accurate, stable conformation of loop L4 and proper active site formation in the mature enzyme.
Thermodynamic, enzymatic and structural effects of removing a salt bridge at the base of loop 4 in (pro)caspase-3.,Walters J, Swartz P, Mattos C, Clark AC Arch Biochem Biophys. 2011 Jan 23. PMID:21266160[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Nicholson DW, Ali A, Thornberry NA, Vaillancourt JP, Ding CK, Gallant M, Gareau Y, Griffin PR, Labelle M, Lazebnik YA, et al.. Identification and inhibition of the ICE/CED-3 protease necessary for mammalian apoptosis. Nature. 1995 Jul 6;376(6535):37-43. PMID:7596430 doi:http://dx.doi.org/10.1038/376037a0
- ↑ Cabrera JR, Bouzas-Rodriguez J, Tauszig-Delamasure S, Mehlen P. RET modulates cell adhesion via its cleavage by caspase in sympathetic neurons. J Biol Chem. 2011 Apr 22;286(16):14628-38. doi: 10.1074/jbc.M110.195461. Epub, 2011 Feb 28. PMID:21357690 doi:10.1074/jbc.M110.195461
- ↑ Walters J, Swartz P, Mattos C, Clark AC. Thermodynamic, enzymatic and structural effects of removing a salt bridge at the base of loop 4 in (pro)caspase-3. Arch Biochem Biophys. 2011 Jan 23. PMID:21266160 doi:10.1016/j.abb.2011.01.011
