TY - JOUR
T1 - Inhibition of the CaaX proteases Rce1p and Ste24p by peptidyl (acyloxy)methyl ketones
AU - Porter, Stephen B.
AU - Hildebrandt, Emily R.
AU - Breevoort, Sarah R.
AU - Mokry, David Z.
AU - Dore, Timothy M.
AU - Schmidt, Walter K.
N1 - Funding Information:
We are grateful to Drs. Claiborne Glover, Kelley Moremen, Jim Travis (all of the University of Georgia), and Jan Potempa (Jagiellonian University, Poland) for technical advice, critical discussions, and access to equipment, Wyeth Pharmaceuticals for providing initial samples of the fluorogenic K-Ras peptide substrates, Dr. Matthew Bogyo (Stanford University) for providing FR, YFR, FG, and YFG based AOMKs, and Andrea Lapham-Cardenas and Victoria Rogers for expert technical assistance. This work was supported by a Georgia Cancer Coalition Distinguished Cancer Clinician/Scientist Scholar award, a grant from the National Institutes of Health (to WKS), and an NIH research grant supplement to Promote Diversity in Health-Related Research (for SBP).
PY - 2007/6
Y1 - 2007/6
N2 - The CaaX proteases Rce1p and Ste24p can independently promote a proteolytic step required for the maturation of certain isoprenylated proteins. Although functionally related, Rce1p and Ste24p are unrelated in primary sequence. They have distinct enzymatic properties, which are reflected in part by their distinct inhibitor profiles. Moreover, Rce1p has an undefined catalytic mechanism, whereas Ste24p is an established zinc-dependent metalloprotease. This study demonstrates that both enzymes are inhibited by peptidyl (acyloxy)methyl ketones (AOMKs), making these compounds the first documented dual specificity inhibitors of the CaaX proteases. Further investigation of AOMK-mediated inhibition reveals that varying the peptidyl moiety can significantly alter the inhibitory properties of AOMKs toward Rce1p and Ste24p and that these enzymes display subtle differences in sensitivity to AOMKs. This observation suggests that this compound class could potentially be engineered to be selective for either of the CaaX proteases. We also demonstrate that the reported sensitivity of Rce1p to TPCK is substrate-dependent, which significantly alters the interpretation of certain reports having used TPCK sensitivity for mechanistic classification of Rce1p. Finally, we show that an AOMK inhibits the isoprenylcysteine carboxyl methyltransferase Ste14p. In sum, our observations raise important considerations regarding the specificity of agents targeting enzymes involved in the maturation of isoprenylated proteins, some of which are being developed as anti-cancer therapeutic agents.
AB - The CaaX proteases Rce1p and Ste24p can independently promote a proteolytic step required for the maturation of certain isoprenylated proteins. Although functionally related, Rce1p and Ste24p are unrelated in primary sequence. They have distinct enzymatic properties, which are reflected in part by their distinct inhibitor profiles. Moreover, Rce1p has an undefined catalytic mechanism, whereas Ste24p is an established zinc-dependent metalloprotease. This study demonstrates that both enzymes are inhibited by peptidyl (acyloxy)methyl ketones (AOMKs), making these compounds the first documented dual specificity inhibitors of the CaaX proteases. Further investigation of AOMK-mediated inhibition reveals that varying the peptidyl moiety can significantly alter the inhibitory properties of AOMKs toward Rce1p and Ste24p and that these enzymes display subtle differences in sensitivity to AOMKs. This observation suggests that this compound class could potentially be engineered to be selective for either of the CaaX proteases. We also demonstrate that the reported sensitivity of Rce1p to TPCK is substrate-dependent, which significantly alters the interpretation of certain reports having used TPCK sensitivity for mechanistic classification of Rce1p. Finally, we show that an AOMK inhibits the isoprenylcysteine carboxyl methyltransferase Ste14p. In sum, our observations raise important considerations regarding the specificity of agents targeting enzymes involved in the maturation of isoprenylated proteins, some of which are being developed as anti-cancer therapeutic agents.
KW - (acyloxy)methyl ketone
KW - CaaX protein
KW - Isoprenylation
KW - Post-translational modification
KW - Protease
KW - Ras
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U2 - 10.1016/j.bbamcr.2007.03.004
DO - 10.1016/j.bbamcr.2007.03.004
M3 - Article
C2 - 17467817
AN - SCOPUS:34249690834
VL - 1773
SP - 853
EP - 862
JO - Biochimica et Biophysica Acta - Molecular Cell Research
JF - Biochimica et Biophysica Acta - Molecular Cell Research
SN - 0167-4889
IS - 6
ER -