scholarly journals Kelch Repeat Protein Clakel2p and Calcium Signaling Control Appressorium Development in Colletotrichum lagenarium

2007 ◽  
Vol 7 (1) ◽  
pp. 102-111 ◽  
Author(s):  
Ayumu Sakaguchi ◽  
Toshihiko Miyaji ◽  
Gento Tsuji ◽  
Yasuyuki Kubo
Keyword(s):  
Microtubule Assembly ◽  
Calcium Signal ◽  
Cellular Polarity ◽  
Appressorium Formation ◽  
Cellular Functions ◽  
Colletotrichum Lagenarium ◽  
Cucumber Cotyledon ◽  
Penetration Ability ◽  
Cellulose Membranes ◽  
Appressorium Development

ABSTRACT Kelch repeat proteins are important mediators of fundamental cellular functions and are found in diverse organisms. However, the roles of these proteins in filamentous fungi have not been characterized. We isolated a kelch repeat-encoding gene of Colletotrichum lagenarium ClaKEL2, a Schizosaccharomyces pombe tea1 homologue. Analysis of the clakel2 mutant indicated that ClaKEL2 was required for the establishment of cellular polarity essential for proper morphogenesis of appressoria and that there is a plant signal-specific bypass pathway for appressorium development which circumvents ClaKEL2 function. Clakel2p was localized in the polarized region of growing hyphae and germ tubes, and the localization was disturbed by a microtubule assembly blocker. The clakel2 mutants formed abnormal appressoria, and those appressoria were defective in penetration hypha development into cellulose membranes, an artificial model substrate for fungal infection. Surprisingly, the clakel2 mutants formed normal appressoria on the host plant and retained penetration ability. Normal appressorium formation on the artificial substrate by the clakel2 mutants was restored when cells were incubated in the presence of CaCl2 or exudates from cucumber cotyledon. Furthermore, calcium channel modulators inhibited restoration of normal appressorium formation. These results suggest that there could be a bypass pathway that transduces a plant-derived signal for appressorium development independent of ClaKEL2 and that a calcium signal is involved in this transduction pathway.

Effects of temperature and antibiotics on appressorium formation in spores of Colletotrichum lagenarium

1977 ◽  
Vol 23 (5) ◽  
pp. 626-629 ◽  
Author(s):  
Machiko Tani ◽  
Norio Ishida ◽  
Iwao Furusawa
Keyword(s):  
Spore Germination ◽  
Germ Tube ◽  
Temperature Treatment ◽  
Appressorium Formation ◽  
Colletotrichum Lagenarium ◽  
Effects Of Temperature ◽  
Blasticidin S

Effects of temperature (32 °C), cycloheximide, and blasticidin-S on spore germination and appressorium formation of Colletotrichum lagenarium were investigated. Temperature treatment at 32 °C, given just before the emergence of the germ tube 4 h after incubation at 24 °C, significantly inhibited appressorium formation. Cycloheximide (1 ppm) or blasticidin-S (7 ppm) appeared to have reversed the effect of 32 °C treatment by producing appressoria in 30% of the germinated spores.

scholarly journals Magnaporthe oryzae Auxiliary Activity Protein MoAa91 Functions as Chitin-Binding Protein To Induce Appressorium Formation on Artificial Inductive Surfaces and Suppress Plant Immunity

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Ying Li ◽  
Xinyu Liu ◽  
Muxing Liu ◽  
Yang Wang ◽  
Yibin Zou ◽  
...  
Keyword(s):  
Magnaporthe Oryzae ◽  
Binding Protein ◽  
Plant Immunity ◽  
G Protein Signaling ◽  
Protein Signaling ◽  
Appressorium Formation ◽  
Protein Precursor ◽  
Content Type ◽  
Surface Recognition ◽  
Appressorium Development

ABSTRACT The appressoria that are generated by the rice blast fungus Magnaporthe oryzae in response to surface cues are important for successful colonization. Previous work showed that regulators of G-protein signaling (RGS) and RGS-like proteins play critical roles in appressorium formation. However, the mechanisms by which these proteins orchestrate surface recognition for appressorium induction remain unclear. Here, we performed comparative transcriptomic studies of ΔMorgs mutant and wild-type strains and found that M. oryzae Aa91 (MoAa91), a homolog of the auxiliary activity family 9 protein (Aa9), was required for surface recognition of M. oryzae. We found that MoAA91 was regulated by the MoMsn2 transcription factor and that its disruption resulted in defects in both appressorium formation on the artificial inductive surface and full virulence of the pathogen. We further showed that MoAa91 was secreted into the apoplast space and was capable of competing with the immune receptor chitin elicitor-binding protein precursor (CEBiP) for chitin binding, thereby suppressing chitin-induced plant immune responses. In summary, we have found that MoAa91 is a novel signaling molecule regulated by RGS and RGS-like proteins and that MoAa91 not only governs appressorium development and virulence but also functions as an effector to suppress host immunity. IMPORTANCE The rice blast fungus Magnaporthe oryzae generates infection structure appressoria in response to surface cues largely due to functions of signaling molecules, including G-proteins, regulators of G-protein signaling (RGS), mitogen-activated protein (MAP) kinase pathways, cAMP signaling, and TOR signaling pathways. M. oryzae encodes eight RGS and RGS-like proteins (MoRgs1 to MoRgs8), and MoRgs1, MoRgs3, MoRgs4, and MoRgs7 were found to be particularly important in appressorium development. To explore the mechanisms by which these proteins regulate appressorium development, we have performed a comparative in planta transcriptomic study and identified an auxiliary activity family 9 protein (Aa9) homolog that we named MoAa91. We showed that MoAa91 was secreted from appressoria and that the recombinant MoAa91 could compete with a chitin elicitor-binding protein precursor (CEBiP) for chitin binding, thereby suppressing chitin-induced plant immunity. By identifying MoAa91 as a novel signaling molecule functioning in appressorium development and an effector in suppressing host immunity, our studies revealed a novel mechanism by which RGS and RGS-like proteins regulate pathogen-host interactions.

scholarly journals TAMI-04. TUMOR TREATING FIELDS (TTFIELDS) HINDER GLIOMA CELL MOTILITY THROUGH REGULATION OF MICROTUBULE AND ACTIN DYNAMICS

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii213-ii213
Author(s):  
Tali Voloshin ◽  
Rosa Schneiderman ◽  
Alexandra Volodin ◽  
Reuben Shamir ◽  
Noa Kaynan ◽  
...  
Keyword(s):  
Cell Motility ◽  
Glioma Cell ◽  
Therapeutic Potential ◽  
Adhesion Formation ◽  
Glioma Cells ◽  
Microtubule Assembly ◽  
Actin Dynamics ◽  
Treatment Modalities ◽  
Cellular Polarity ◽  
Tumor Treating Fields

Abstract The ability of glioma cells to invade adjacent brain tissue remains a major obstacle to therapeutic disease management. Therefore, the development of novel treatment modalities that disrupt glioma cell motility could facilitate greater disease control. Tumor Treating Fields (TTFields), encompassing alternating electric fields within the intermediate frequency range, is an anticancer treatment delivered to the tumor region through transducer arrays placed non-invasively on the skin. This novel loco-regional treatment has demonstrated efficacy and safety and is FDA-approved in patients with glioblastoma and malignant pleural mesothelioma. TTFields are currently being investigated in other solid tumors in ongoing trials, including the phase 3 METIS trial (brain metastases from NSCLC; NCT02831959). Although established as an anti-mitotic treatment, the anti-metastatic potential of TTFields and its effects on cytoskeleton rapid dynamics during cellular motility warrant further investigation. Previous studies have demonstrated that TTFields inhibits metastatic properties of cancer cells. Identification of a unifying mechanism connecting the versatile TTFields-induced molecular responses is required to optimize the therapeutic potential of TTFields. In this study, confocal microscopy, computational tools, and biochemical analyses were utilized to show that TTFields disrupt glioma cellular polarity by interfering with microtubule assembly and directionality. Under TTFields application, changes in microtubule organization resulted in activation of GEF-H1, which led to an increase in active RhoA levels and consequent focal adhesion formation with actin cytoskeleton architectural changes. Furthermore, the optimal TTFields frequency for inhibition of invasion in glioma cells was 300 kHz, which differed from the optimal anti-mitotic frequency leading to glioma cell death of 200 kHz. The inhibitory effect of TTFields on migration was observed at fields intensities of 0.6 V/cm RMS (below the threshold of 1 V/cm RMS previously reported for cytotoxic effects). Together, these data identify discrete TTFields effects that disrupt processes crucial for glioma cell motility.

scholarly journals Protein Synthesis during Germination and Appressorium Formation of Colletotrichum lagenarium Spores

Microbiology ◽  
1981 ◽  
Vol 124 (1) ◽  
pp. 61-69 ◽  
Author(s):  
K. SUZUKI ◽  
I. FURUSAWA ◽  
N. ISHIDA ◽  
M. YAMAMOTO
Keyword(s):  
Protein Synthesis ◽  
Appressorium Formation ◽  
Colletotrichum Lagenarium

scholarly journals The Colletotrichum lagenarium Ste12-Like Gene CST1 Is Essential for Appressorium Penetration

2003 ◽  
Vol 16 (4) ◽  
pp. 315-325 ◽  
Author(s):  
Gento Tsuji ◽  
Satoshi Fujii ◽  
Seiji Tsuge ◽  
Tomonori Shiraishi ◽  
Yasuyuki Kubo
Keyword(s):  
Map Kinase ◽  
Lipid Droplets ◽  
Map Kinases ◽  
Cellulose Membrane ◽  
Appressorium Formation ◽  
Colletotrichum Lagenarium ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Map Kinase Pathway ◽  
Kinase Pathway

Colletotrichum lagenarium is the causal agent of anthracnose of cucumber. This fungus produces a darkly melanized infection structure, appressoria, to penetrate the host leaves. The C. lagenarium CMK1 gene, a homologue of the Saccharomyces cerevisiae FUS3/KSS1 mitogen-activated protein (MAP) kinase genes, was shown to regulate conidial germination, appressorium formation, and invasive growth. In S. cerevisiae, Ste12p is known to be a transcriptional factor downstream of Fus3p/Kss1p MAP kinases. To evaluate the CMK1 MAP kinase pathway, we isolated the Ste12 homologue CST1 gene from C. lagenarium and characterized. The cst1Δ strains were nonpathogenic on intact host leaves, but could form lesions when inoculated on wounded leaves. Conidia of the cst1Δ strains could germinate and form melanized appressoria on both host leaf surface and artificial cellulose membrane, but could not produce infectious hyphae from appressoria, suggesting that CST1 is essential for appressorium penetration in C. lagenarium. In addition, matured appressoria of the cst1Δ strains contained an extremely low level of lipid droplets compared with that of the wild-type strain. Lipid droplets were abundant in conidia of the cst1Δ strains, but rapidly disappeared during appressorium formation. This misscheduled lipid degradation might be related to the failure of appressorium penetration in the cst1Δ strain.

scholarly journals β-Tubulin carboxy-terminal tails exhibit isotype-specific effects on microtubule dynamics in human gene-edited cells

2018 ◽  
Vol 1 (2) ◽  
pp. e201800059 ◽  
Author(s):  
Amelia L Parker ◽  
Wee Siang Teo ◽  
Elvis Pandzic ◽  
Juan Jesus Vicente ◽  
Joshua A McCarroll ◽  
...  
Keyword(s):  
Dynamic Properties ◽  
Fluorescent Microscopy ◽  
Microtubule Dynamics ◽  
Fine Tuning ◽  
Microtubule Assembly ◽  
Cellular Functions ◽  
Microtubule Network ◽  
Tubulin Isotypes ◽  
Carboxy Terminal ◽  
Β Tubulin

Microtubules are highly dynamic structures that play an integral role in fundamental cellular functions. Different α- and β-tubulin isotypes are thought to confer unique dynamic properties to microtubules. The tubulin isotypes have highly conserved structures, differing mainly in their carboxy-terminal (C-terminal) tail sequences. However, little is known about the importance of the C-terminal tail in regulating and coordinating microtubule dynamics. We developed syngeneic human cell models using gene editing to precisely modify the β-tubulin C-terminal tail region while preserving the endogenous microtubule network. Fluorescent microscopy of live cells, coupled with advanced image analysis, revealed that the β-tubulin C-terminal tails differentially coordinate the collective and individual dynamic behavior of microtubules by affecting microtubule growth rates and explorative microtubule assembly in an isotype-specific manner. Furthermore, βI- and βIII-tubulin C-terminal tails differentially regulate the sensitivity of microtubules to tubulin-binding agents and the microtubule depolymerizing protein mitotic centromere-associated kinesin. The sequence of the β-tubulin tail encodes regulatory information that instructs and coordinates microtubule dynamics, thereby fine-tuning microtubule dynamics to support cellular functions.

scholarly journals The size of helical pitch is important for microtubule plus end dynamic instability

2020 ◽  
Author(s):  
Chenshu Liu ◽  
Louis Prahl ◽  
Yu He ◽  
Yan Wang ◽  
Ruijun Zhu ◽  
...  
Keyword(s):  
Intracellular Transport ◽  
Dynamic Instability ◽  
Chemotherapeutic Agents ◽  
Stochastic Simulations ◽  
Microtubule Assembly ◽  
Hydrolysis Rate ◽  
Cellular Functions ◽  
Helical Pitch ◽  
Division Cell ◽  
The Impact

ABSTRACTMicrotubule (MT) dynamic instability is a conserved phenomenon underlying essential cellular functions such as cell division, cell migration and intracellular transport, and is a key target of many chemotherapeutic agents. However, it remains unclear how the organization of tubulin dimers at the nanometer scale translates into dynamic instability as an emergent property at the micrometer scale. Tubulin dimers are organized into left-handed helical MT lattice, and most present-day MTs converge at a 1.5 dimer helical pitch that causes a seam in an otherwise symmetric helix. Because presently there are no experimental methods that can precisely manipulate tubulin subunit with sub-dimer resolution, the impact of helical pitch on dynamic instability remains unknown. Here by using stochastic simulations of microtubule assembly dynamics we demonstrate that helical pitch plays essential roles in MT plus end dynamic instability. By systematically altering helical pitch size, one half-dimer at a time, we found that a helical pitch as small as one half-dimer is sufficient to inhibit short-term MT length plateaus associated with diminishing GTP-tubulin cap. Notably, MT plus end dynamics quantitatively scale with the size of helical pitch, rather than being clustered by the presence or absence of helical symmetry. Microtubules with a 1.5 dimer helical pitch exhibit growth and shrinkage phases and undergo catastrophe and rescue similar to experimentally observed microtubules. Reducing helical pitch to 0 promotes rapid disassembly, while increasing it causes microtubules to undergo persistent growth, and it is the 1.5 dimer helical pitch that yields the highest percentage of MTs that undergo alternating growth and shrinkage without being totally disassembled. Finally, although the 1.5 dimer helical pitch is conserved among most present-day MTs, we find that other parameters, such as GTP hydrolysis rate, can partially compensate for changes in helical pitch. Together our results indicate that helical pitch is a determinant of MT plus end dynamic instability and that the evolutionarily conserved 1.5 dimer helical pitch promotes dynamic instability required for microtubule-dependent cellular functions.

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