title: Signaling function of alpha-catenin in microtubule regulation.
abstract: Centrosomes control microtubule dynamics in many cell types, and their removal from the cytoplasm leads to a shift from dynamic instability to treadmilling behavior and to a dramatic decrease of microtubule mass (Rodionov et al., 1999; PNAS 96:115). In cadherin-expressing cells, these effects can be reversed:non-centrosomal cytoplasts that form cadherin-mediated adherens junctions display dense arrays of microtubules (Chausovsky et al., 2000; Nature Cell Biol 2:797). In adherens junctions, cadherin's cytoplasmic domain binds p120 catenin and beta-catenin, which in turn binds alpha-catenin. To elucidate the roles of the cadherin-associated proteins in regulating microtubule dynamics, we prepared GFP-tagged, plasma membrane targeted or untargeted p120 catenin, alpha-catenin and beta-catenin and tested their ability to rescue the loss of microtubule mass caused by centrosomal removal in the poorly adhesive cell line CHO-K1. Only membrane targeting of alpha-catenin led to a significant increase in microtubule length and density in centrosome-free cytoplasts. Expression of non-membrane-targeted alpha-catenin produced only a slight effect, while both membrane-targeted and non-targeted p120 and beta-catenin were ineffective in this assay. Together, these findings suggest that alpha-catenin is able to regulate microtubule dynamics in a centrosome-independent manner.
authors.affiliation: Cancer Center, Ordway Research Institute, Albany, New York, USA. mshtutman@ordwayresearch.org
authors.forename: Michael
authors.initials: M
authors.lastname: Shtutman
authors.forename: Alexander
authors.initials: A
authors.lastname: Chausovsky
authors.forename: Masha
authors.initials: M
authors.lastname: Prager-Khoutorsky
authors.forename: Natalia
authors.initials: N
authors.lastname: Schiefermeier
authors.forename: Shlomit
authors.initials: S
authors.lastname: Boguslavsky
authors.forename: Zvi
authors.initials: Z
authors.lastname: Kam
authors.forename: Elaine
authors.initials: E
authors.lastname: Fuchs
authors.forename: Benjamin
authors.initials: B
authors.lastname: Geiger
authors.forename: Gary G
authors.initials: GG
authors.lastname: Borisy
authors.forename: Alexander D
authors.initials: AD
authors.lastname: Bershadsky
mesh_terms: D000818:Animals; D016466:CHO Cells; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D018385:Centrosome / Q000502:physiology; D006224:Cricetinae; D003412:Cricetulus; D003593:Cytoplasm / Q000648:ultrastructure; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D021381:Protein Transport; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection; D051178:alpha Catenin / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D015820:Cadherins; D051178:alpha Catenin