Article

TIP maker and TIP marker; EB1 as a master controller of microtubule plus ends

Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.
The Journal of Cell Biology (Impact Factor: 9.69). 11/2005; 171(2):197-200. DOI: 10.1083/jcb.200509150
Source: PubMed

ABSTRACT The EB1 protein is a member of the exciting and enigmatic family of microtubule (MT) tip-tracking proteins. EB1 acts as an exquisite marker of dynamic MT plus ends in some cases, whereas in others EB1 is thought to directly dictate the behavior of the plus ends. How EB1 differentiates between these two roles remains unclear; however, a growing list of interactions between EB1 and other MT binding proteins suggests there may be a single mechanism. Adding another layer of complexity to these interactions, two studies published in this issue implicate EB1 in cross-talk between mitotic MTs and between MTs and actin filaments (Goshima et al., p. 229; Wu et al., p. 201). These results raise the possibility that EB1 is a central player in MT-based transport, and that the activity of MT-binding proteins depends on their ability or inability to interact with EB1.

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    • "EB1 localizes to the microtubule plus end, at least in part, by recognizing the nucleotide state of tubulin in the microtubule lattice [Zanic et al., 2009; Maurer et al., 2011, 2012]. There is evidence that the EB1 N-terminal domain binds to the microtubule preferentially through interactions with the GTP-rich cap, whereas the C-terminal domain acts as a microtubule tip localization signal and enables binding to many other 1TIPs [Hayashi and Ikura, 2003; Vaughan, 2005; Honnappa et al., 2009; Zanic et al., 2009]. EB1 impacts numerous biological functions including the suppression of microtubule dynamic instability [Manna et al., 2008], regulation of microtubule dynamics and chromosomal stability [Leterrier et al., 2011], as well as maintenance of cell polarity through activation of protein kinase C [Schober et al., 2012]. "
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    • "eb1 triple-mutants exhibit only mild phenotypes associated with root responses to touch and gravity (Bisgrove et al. 2008). EB1 proteins associate with plus ends of MTs where they regulate polymerization rates (Tirnauer et al. 2004), they serve as integrators of protein complex assembly at MT plus ends (Vaughan 2005), and they facilitate the delivery of proteins to specific sites at the cortex (Canman et al. 2003). To date, the significance of EB1 localization at the PPB is not resolved, although reports on a subtype of EB1c in Arabidopsis suggest some function in spindle formation (Komaki et al. 2010). "
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