QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

doi: 10.1242/10.1242/jcs.00205

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Segerman, B. Articles by Gullberg, M. Search for Related Content PubMed PubMed Citation Articles by Segerman, B. Articles by Gullberg, M. Social Bookmarking                         What's this?

Autonomous and phosphorylation-responsive microtubule-regulating activities of the N-terminus of Op18/stathmin

¹ Department of Molecular Biology, Umeå University, Sweden
² Department of Biological Sciences, Lehigh University, Bethlehem, PA, USA

^* Author for correspondence (e-mail: Martin.Gullberg{at}molbiol.umu.se)

Accepted 2 October 2002

Op18 is the prototypical member of a family of phosphorylation-responsive regulators of microtubule (MT) dynamics. Previous dissection of Op18 has suggested that it has a functional dichotomy in which an intact N-terminus is required for catastrophe promotion (i.e. transition from growing to shrinking MTs), whereas an intact C-terminus is required for efficient ternary Op18-tubulin complex formation and the resultant tubulin-sequestering activity. Here we have expressed and functionally analyzed the properties of the N-terminus of Op18. The data show that the N-terminal 57 residues are sufficient for low-affinity tubulin interactions, as shown by inhibition of basal GTP hydrolysis of soluble heterodimers. In addition, high concentrations of the Op18 N-terminal portion increased the catastrophe rate during MT assembly in vitro. Overexpression of the N-terminus in a human cell line results in MT destabilization in interphase and phosphorylation-modulated accumulation of metaphase-arrested cells with dense short MTs. These results demonstrate that the N-terminus of Op18 has autonomous activity. Evidently, this activity is enhanced by the increase in tubulin affinity that is provided by the extended -helical portion of native Op18.

Key words: Microtubule, Phosphoprotein, Oncoprotein 18, GTP Phosphohydrolase

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				K. Brannstrom, M. E. Sellin, P. Holmfeldt, M. Brattsand, and M. Gullberg The Schistosoma mansoni Protein Sm16/SmSLP/SmSPO-1 Assembles into a Nine-Subunit Oligomer with Potential To Inhibit Toll-Like Receptor Signaling Infect. Immun., March 1, 2009; 77(3): 1144 - 1154. [Abstract] [Full Text] [PDF]

				T. Wittmann, G. M. Bokoch, and C. M. Waterman-Storer Regulation of Microtubule Destabilizing Activity of Op18/Stathmin Downstream of Rac1 J. Biol. Chem., February 13, 2004; 279(7): 6196 - 6203. [Abstract] [Full Text] [PDF]

				S. Honnappa, B. Cutting, W. Jahnke, J. Seelig, and M. O. Steinmetz Thermodynamics of the Op18/Stathmin-Tubulin Interaction J. Biol. Chem., October 3, 2003; 278(40): 38926 - 38934. [Abstract] [Full Text] [PDF]

				P. Holmfeldt, K. Brannstrom, S. Stenmark, and M. Gullberg Deciphering the Cellular Functions of the Op18/Stathmin Family of Microtubule-Regulators by Plasma Membrane-targeted Localization Mol. Biol. Cell, September 1, 2003; 14(9): 3716 - 3729. [Abstract] [Full Text] [PDF]

				K. Brannstrom, B. Segerman, and M. Gullberg Molecular Dissection of GTP Exchange and Hydrolysis within the Ternary Complex of Tubulin Heterodimers and Op18/Stathmin Family Members J. Biol. Chem., May 2, 2003; 278(19): 16651 - 16657. [Abstract] [Full Text] [PDF]