TY - JOUR
T1 - Hallmarks of molecular action of microtubule stabilizing agents
T2 - Effects of epothilone B, ixabepilone, peloruside A, and laulimalide on microtubule conformation
AU - Khrapunovich-Baine, Marina
AU - Menon, Vilas
AU - Yang, Chia Ping Huang
AU - Northcote, Peter T.
AU - Miller, John H.
AU - Angeletti, Ruth Hogue
AU - Fiser, Andras
AU - Horwitz, Susan Band
AU - Xiao, Hui
PY - 2011/4/1
Y1 - 2011/4/1
N2 - Microtubule stabilizing agents (MSAs) comprise a class of drugs that bind to microtubule (MT) polymers and stabilize them against disassembly. Several of these agents are currently in clinical use as anticancer drugs, whereas others are in various stages of development. Nonetheless, there is insufficient knowledge about the molecular modes of their action. Recent studies from our laboratory utilizing hydrogen-deuterium exchange in combination with mass spectrometry (MS) provide new information on the conformational effects of Taxol and discodermolide on microtubules isolated from chicken erythrocytes (CET).Wereport here a comprehensive analysis of the effects of epothilone B, ixabepilone (IXEMPRA™), laulimalide, and peloruside A on CET conformation. The results of our comparative hydrogen-deuterium exchange MS studies indicate that all MSAs have significant conformational effects on the C-terminal H12 helix of α-tubulin, which is a likely molecular mechanism for the previously observed modulations of MT interactions with microtubule-associated and motor proteins. More importantly, the major mode of MT stabilization by MSAs is the tightening of the longitudinal interactions between two adjacent αβ-tubulin heterodimers at the interdimer interface. In contrast to previous observations reported with bovine brain tubulin, the lateral interactions between the adjacent protofilaments in CET are particularly strongly stabilized by peloruside A and laulimalide, drugs that bind outside the taxane site. This not only highlights the significance of tubulin isotype composition in modulating drug effects on MT conformation and stability but also provides a potential explanation for the synergy observed when combinations of taxane and alternative site binding drugs are used.
AB - Microtubule stabilizing agents (MSAs) comprise a class of drugs that bind to microtubule (MT) polymers and stabilize them against disassembly. Several of these agents are currently in clinical use as anticancer drugs, whereas others are in various stages of development. Nonetheless, there is insufficient knowledge about the molecular modes of their action. Recent studies from our laboratory utilizing hydrogen-deuterium exchange in combination with mass spectrometry (MS) provide new information on the conformational effects of Taxol and discodermolide on microtubules isolated from chicken erythrocytes (CET).Wereport here a comprehensive analysis of the effects of epothilone B, ixabepilone (IXEMPRA™), laulimalide, and peloruside A on CET conformation. The results of our comparative hydrogen-deuterium exchange MS studies indicate that all MSAs have significant conformational effects on the C-terminal H12 helix of α-tubulin, which is a likely molecular mechanism for the previously observed modulations of MT interactions with microtubule-associated and motor proteins. More importantly, the major mode of MT stabilization by MSAs is the tightening of the longitudinal interactions between two adjacent αβ-tubulin heterodimers at the interdimer interface. In contrast to previous observations reported with bovine brain tubulin, the lateral interactions between the adjacent protofilaments in CET are particularly strongly stabilized by peloruside A and laulimalide, drugs that bind outside the taxane site. This not only highlights the significance of tubulin isotype composition in modulating drug effects on MT conformation and stability but also provides a potential explanation for the synergy observed when combinations of taxane and alternative site binding drugs are used.
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U2 - 10.1074/jbc.M110.162214
DO - 10.1074/jbc.M110.162214
M3 - Article
C2 - 21245138
AN - SCOPUS:79953232399
SN - 0021-9258
VL - 286
SP - 11765
EP - 11778
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 13
ER -