The Role of Microtubules in Rapid Hyphal Tip Growth of<i>Aspergillus nidulans</i>

Horio, Tetsuya; Oakley, Berl R

doi:10.1091/mbc.e04-09-0798

Cited by 178 publications

(203 citation statements)

References 32 publications

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“…We first verified that benomyl was depolymerizing microtubules as expected using a GFP-␣-tubulin fusion (Horio and Oakley, 2005). After benomyl addition, as noted previously, growth of the tip slowed.…”

Section: Effects Of Antimicrotubule Agent Benomyl On Tip Growth and Tsupporting

confidence: 64%

“…We prefer to use lower concentrations because they are less likely to have secondary effects. Benomyl was stored and used as reported previously (Horio and Oakley, 2005). For washout experiments, the culture medium containing the inhibitor was gently removed from the observation chambers with a transfer pipette and replaced with medium without inhibitor.…”

Section: Inhibitor Treatmentsmentioning

confidence: 99%

“…For brevity, we use the term "tip" for the general tip region and "apex" for the extreme tip of the cell. As germ tubes extend and rounds of asymmetrical cell divisions occur, tip growth accelerates approximately fivefold (Horio and Oakley, 2005), and this is accompanied by a reorganization of actin patches into a prominent ring or collar 1-2 m behind the hyphal apex ( Figure 1C). Actin patches are generally not present A maximum intensity projection of a Z-series stack from a set of time-lapse images showing actin in two swollen conidia (asexual spores).…”

Section: Localization and Imaging Of Actin And Tropomyosin In Living mentioning

confidence: 99%

“…As expected, actin cables disassembled rapidly upon addition of cytochalasin A, and they were undetectable 5 min after cytochalasin A addition. Horio and Oakley (2005) have studied the effects of the antimicrotubule agent benomyl on tip growth. From these and previous studies (e.g., Oakley and Morris, 1981), it is clear that benomyl is an excellent antimicrotubule agent in A. nidulans.…”

Section: Effects Of the Anti-actin Agents Cytochalasin A And Latruncumentioning

confidence: 99%

“…It causes rapid microtubule disassembly (all microtubules disassemble in Ͻ10 min after addition to the culture chamber), it is rapidly reversible (microtubules begin to reassemble in Ͻ5 min after benomyl is washed out), and it is quite specific for microtubules (Oakley and Morris, 1981). Treatment with benomyl caused a dramatic reduction in tip growth rate but not a complete stoppage of growth (Horio and Oakley, 2005). It was also noted that benomyl treatment led to growth away from the tip.…”

Section: Effects Of the Anti-actin Agents Cytochalasin A And Latruncumentioning

confidence: 99%

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The Tip Growth Apparatus ofAspergillus nidulans

Taheri-Talesh

Horio

Araújo‐Bazán

et al. 2008

MBoC

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Hyphal tip growth in fungi is important because of the economic and medical importance of fungi, and because it may be a useful model for polarized growth in other organisms. We have investigated the central questions of the roles of cytoskeletal elements and of the precise sites of exocytosis and endocytosis at the growing hyphal tip by using the model fungus Aspergillus nidulans. Time-lapse imaging of fluorescent fusion proteins reveals a remarkably dynamic, but highly structured, tip growth apparatus. Live imaging of SYNA, a synaptobrevin homologue, and SECC, an exocyst component, reveals that vesicles accumulate in the Spitzenkö rper (apical body) and fuse with the plasma membrane at the extreme apex of the hypha. SYNA is recycled from the plasma membrane by endocytosis at a collar of endocytic patches, 1-2 m behind the apex of the hypha, that moves forward as the tip grows. Exocytosis and endocytosis are thus spatially coupled. Inhibitor studies, in combination with observations of fluorescent fusion proteins, reveal that actin functions in exocytosis and endocytosis at the tip and in holding the tip growth apparatus together. Microtubules are important for delivering vesicles to the tip area and for holding the tip growth apparatus in position. INTRODUCTIONPolarized cell growth occurs in most eukaryotic phyla, and it includes a plethora of important phenomena, such as neuronal growth cone extension in animals and pollen tube extension in vascular plants. It is particularly important in filamentous fungi where nearly all growth occurs by hyphal tip extension (reviewed by Momany, 2002). Given that some filamentous fungi are important fermentation organisms, the growth of which is of considerable economic importance, whereas others are serious plant, animal, and human pathogens, there is considerable interest in the mechanisms of tip growth in these organisms.A great deal of progress has been made in understanding fungal tip growth (summarized by Harris et al., 2005; Steinberg, 2007a,b;Riquelme et al., 2007), but key questions remain unanswered. There is general agreement that fungal tip growth involves the synthesis of cell wall components in the cell body, the incorporation of these components into vesicles, the transport of these vesicles to the cell tip, the fusion of these vesicles with the plasma membrane in the area of the cell tip (exocytosis) to release their contents, and the cross-linking of the components after release. It is clear that both microtubules and actin microfilaments play important roles in fungal tip growth, but their exact functions are not yet defined. The exact sites of exocytosis and endocytosis also remain to be determined. The positions of the site(s) of exocytosis are particularly important because fungal walls are relatively stiff structures, and once they have formed the shape of the hypha is established. Hyphal shape is thus determined to a very significant extent by where the wall precursors are released from the cytoplasm, i.e., by the positioning of the site(s) of exocyto...

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Section: Effects Of Antimicrotubule Agent Benomyl On Tip Growth and Tsupporting

confidence: 64%

Section: Inhibitor Treatmentsmentioning

confidence: 99%

Section: Localization and Imaging Of Actin And Tropomyosin In Living mentioning

confidence: 99%

Section: Effects Of the Anti-actin Agents Cytochalasin A And Latruncumentioning

confidence: 99%

Section: Effects Of the Anti-actin Agents Cytochalasin A And Latruncumentioning

confidence: 99%

See 3 more Smart Citations

The Tip Growth Apparatus ofAspergillus nidulans

Taheri-Talesh

Horio

Araújo‐Bazán

et al. 2008

MBoC

Self Cite

276

414

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Tip Growth in the MossPhyscomitrella patens

Bezanilla

Perroud

The MossPhyscomitrella Patens

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Asymmetric microtubule arrays organize the endoplasmic reticulum during polarity establishment in the brown alga Silvetia compressa

Peters

Kropf

2010

Cytoskeleton

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Polarity is a fundamental characteristic of most cell types, and is crucial to early development of the brown alga Silvetia compressa. In eukaryotes the cytoskeleton plays an important role in generating cellular asymmetries. While it is known that F-actin is required for polarization and growth in most tip-growing cells, the roles of microtubules are less clear. We examined the distribution and function of microtubules in S. compressa zygotes as they polarized and initiated tip growth. Microtubules formed asymmetric arrays oriented toward the rhizoid hemisphere early in the polarization process. These arrays were spatially coupled with polar adhesive deposition, a marker of the rhizoid pole. Reorientation of the light vector during polarization led to sequential redistribution of polar axis components, with the microtubules and the polar axis reorienting nearly simultaneously, followed by cell wall loosening and then deposition of new polar adhesive. These findings suggested that microtubules may organize and target endomembrane arrays. We therefore examined the distribution of the endoplasmic reticulum during polarization and found it colocalized with microtubules and became targeted toward the rhizoid pole as microtubule asymmetry was generated. Endoplasmic reticulum association with microtubules remained fully intact following pharmacological disruption of F-actin, whereas microtubule disruption led to aggregation of the endoplasmic reticulum around the nucleus. We propose that brown algae utilize microtubules for organization of the endoplasmic reticulum and migration of exocytotic components to the rhizoid cortex, and present a model for polarity establishment to account for these new findings.

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The Role of Microtubules in Rapid Hyphal Tip Growth ofAspergillus nidulans

Cited by 178 publications

References 32 publications

The Tip Growth Apparatus ofAspergillus nidulans

The Tip Growth Apparatus ofAspergillus nidulans

Tip Growth in the MossPhyscomitrella patens

Asymmetric microtubule arrays organize the endoplasmic reticulum during polarity establishment in the brown alga Silvetia compressa

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