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

Vaughan KT - J. Cell Biol. (2005)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA. Vaughan.4@nd.edu

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.

Show MeSH

Related in: MedlinePlus

Functions for EB1 during interphase and mitosis. GFP-EB1 labels MT plus ends at multiple cellular sites where MT search-capture occurs. (A) EB1 has been implicated in search-capture of ER-Golgi transport vesicles and in MT capture at the cell cortex during cytoskeletal reorientation. In these cases, EB1 highlights locations where search-capture is in progress or has identified capture sites. (B) EB1 has also been linked to search-capture sites during mitosis including the kinetochores of chromosomes during prometaphase and locations at the cell cortex where astral MTs can attach. Depletion of EB1 has been shown to induce short MTs that fail to reach the cell cortex. The consequences include mis-orientation of the spindle.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2171192&req=5

fig1: Functions for EB1 during interphase and mitosis. GFP-EB1 labels MT plus ends at multiple cellular sites where MT search-capture occurs. (A) EB1 has been implicated in search-capture of ER-Golgi transport vesicles and in MT capture at the cell cortex during cytoskeletal reorientation. In these cases, EB1 highlights locations where search-capture is in progress or has identified capture sites. (B) EB1 has also been linked to search-capture sites during mitosis including the kinetochores of chromosomes during prometaphase and locations at the cell cortex where astral MTs can attach. Depletion of EB1 has been shown to induce short MTs that fail to reach the cell cortex. The consequences include mis-orientation of the spindle.

Mentions: Despite an explosion of recent work on EB1, the precise function and location of endogenous EB1 at native levels remains unclear. The MT-associated population of EB1 represents a small subset of total EB1, but this subset has received the most attention. The remainder is thought to be largely soluble, similar to the form that dominates the GFP-EB1 expression studies. Immunofluorescence microscopy images suggest that native EB1 is punctate, resembling vesicles or large protein complexes (Morrison et al., 1998; Faulkner et al., 2000; Mimori-Kiyosue et al., 2000). This would be consistent with the extensive colocalization with other membrane-associated proteins such as CLIP-170 and dynactin. However, nonmembranous protein complexes including binding partners such at APC are also described, and the function of these is under investigation (Mimori-Kiyosue et al., 2000; Wen et al., 2004). In these settings, direct interactions between EB1 and other proteins (p150Glued, CLIP-170, and CLASPs) have been interpreted as recruitment mechanisms (Fig. 1). The fact that these binding partners can also bind tubulin directly suggests some transition or sequential loading process at plus ends that will require more work to resolve.


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

Vaughan KT - J. Cell Biol. (2005)

Functions for EB1 during interphase and mitosis. GFP-EB1 labels MT plus ends at multiple cellular sites where MT search-capture occurs. (A) EB1 has been implicated in search-capture of ER-Golgi transport vesicles and in MT capture at the cell cortex during cytoskeletal reorientation. In these cases, EB1 highlights locations where search-capture is in progress or has identified capture sites. (B) EB1 has also been linked to search-capture sites during mitosis including the kinetochores of chromosomes during prometaphase and locations at the cell cortex where astral MTs can attach. Depletion of EB1 has been shown to induce short MTs that fail to reach the cell cortex. The consequences include mis-orientation of the spindle.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2171192&req=5

fig1: Functions for EB1 during interphase and mitosis. GFP-EB1 labels MT plus ends at multiple cellular sites where MT search-capture occurs. (A) EB1 has been implicated in search-capture of ER-Golgi transport vesicles and in MT capture at the cell cortex during cytoskeletal reorientation. In these cases, EB1 highlights locations where search-capture is in progress or has identified capture sites. (B) EB1 has also been linked to search-capture sites during mitosis including the kinetochores of chromosomes during prometaphase and locations at the cell cortex where astral MTs can attach. Depletion of EB1 has been shown to induce short MTs that fail to reach the cell cortex. The consequences include mis-orientation of the spindle.
Mentions: Despite an explosion of recent work on EB1, the precise function and location of endogenous EB1 at native levels remains unclear. The MT-associated population of EB1 represents a small subset of total EB1, but this subset has received the most attention. The remainder is thought to be largely soluble, similar to the form that dominates the GFP-EB1 expression studies. Immunofluorescence microscopy images suggest that native EB1 is punctate, resembling vesicles or large protein complexes (Morrison et al., 1998; Faulkner et al., 2000; Mimori-Kiyosue et al., 2000). This would be consistent with the extensive colocalization with other membrane-associated proteins such as CLIP-170 and dynactin. However, nonmembranous protein complexes including binding partners such at APC are also described, and the function of these is under investigation (Mimori-Kiyosue et al., 2000; Wen et al., 2004). In these settings, direct interactions between EB1 and other proteins (p150Glued, CLIP-170, and CLASPs) have been interpreted as recruitment mechanisms (Fig. 1). The fact that these binding partners can also bind tubulin directly suggests some transition or sequential loading process at plus ends that will require more work to resolve.

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA. Vaughan.4@nd.edu

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.

Show MeSH
Related in: MedlinePlus