TY - JOUR
T1 - RHAMM promotes interphase microtubule instability and mitotic spindle integrity through MEK1/ERK1/2 activity
AU - Tolg, Cornelia
AU - Hamilton, Sara R.
AU - Morningstar, Lyndsey
AU - Zhang, Jing
AU - Zhang, S.
AU - Esguerra, Kenneth V.
AU - Telmer, Patrick G.
AU - Luyt, Len G.
AU - Harrison, Rene
AU - McCarthy, James B.
AU - Turley, Eva A.
PY - 2010/8/20
Y1 - 2010/8/20
N2 - An oncogenic form of RHAMM (receptor for hyaluronan-mediated motility, mouse, amino acids 163-794 termed RHAMMΔ163) is a cell surface hyaluronan receptor and mitotic spindle protein that is highly expressed in aggressive human cancers. Its regulation of mitotic spindle integrity is thought to contribute to tumor progression, but the molecular mechanisms underlying this function have not previously been defined. Here, we report that intracellular RHAMMΔ163 modifies the stability of interphase and mitotic spindle microtubules through ERK1/2 activity. RHAMM-/- mouse embryonic fibroblasts exhibit strongly acetylated interphase microtubules, multi-pole mitotic spindles, aberrant chromosome segregation, and inappropriate cytokinesis during mitosis. These defects are rescued by either expression of RHAMM or mutant active MEK1. Mutational analyses show that RHAMM Δ163 binds to α- and β-tubulin protein via a carboxyl-terminal leucine zipper, but in vitro analyses indicate this interaction does not directly contribute to tubulin polymerization/stability. Co-immunoprecipitation and pulldown assays reveal complexes of RHAMM Δ163, ERK1/2-MEK1, and α- and β-tubulin and demonstrate direct binding ofRHAMMΔ163 to ERK1 via a D-site motif. In vitro kinase analyses, expression of mutant RHAMMΔ163 defective in ERK1 binding in mouse embryonic fibroblasts, and blocking MEK1 activity collectively confirm that the effect of RHAMMΔ163 on interphase and mitotic spindle microtubules is mediated by ERK1/2 activity. Our results suggest a model wherein intracellular RHAMMΔ163 functions as an adaptor protein to control microtubule polymerization during interphase and mitosis as a result of localizing ERK1/2-MEK1 complexes to their tubulin-associated substrates.
AB - An oncogenic form of RHAMM (receptor for hyaluronan-mediated motility, mouse, amino acids 163-794 termed RHAMMΔ163) is a cell surface hyaluronan receptor and mitotic spindle protein that is highly expressed in aggressive human cancers. Its regulation of mitotic spindle integrity is thought to contribute to tumor progression, but the molecular mechanisms underlying this function have not previously been defined. Here, we report that intracellular RHAMMΔ163 modifies the stability of interphase and mitotic spindle microtubules through ERK1/2 activity. RHAMM-/- mouse embryonic fibroblasts exhibit strongly acetylated interphase microtubules, multi-pole mitotic spindles, aberrant chromosome segregation, and inappropriate cytokinesis during mitosis. These defects are rescued by either expression of RHAMM or mutant active MEK1. Mutational analyses show that RHAMM Δ163 binds to α- and β-tubulin protein via a carboxyl-terminal leucine zipper, but in vitro analyses indicate this interaction does not directly contribute to tubulin polymerization/stability. Co-immunoprecipitation and pulldown assays reveal complexes of RHAMM Δ163, ERK1/2-MEK1, and α- and β-tubulin and demonstrate direct binding ofRHAMMΔ163 to ERK1 via a D-site motif. In vitro kinase analyses, expression of mutant RHAMMΔ163 defective in ERK1 binding in mouse embryonic fibroblasts, and blocking MEK1 activity collectively confirm that the effect of RHAMMΔ163 on interphase and mitotic spindle microtubules is mediated by ERK1/2 activity. Our results suggest a model wherein intracellular RHAMMΔ163 functions as an adaptor protein to control microtubule polymerization during interphase and mitosis as a result of localizing ERK1/2-MEK1 complexes to their tubulin-associated substrates.
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U2 - 10.1074/jbc.M110.121491
DO - 10.1074/jbc.M110.121491
M3 - Article
C2 - 20558733
AN - SCOPUS:77956210930
SN - 0021-9258
VL - 285
SP - 26461
EP - 26474
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 34
ER -