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Microtubule plus end‐tracking proteins play critical roles in directional growth of hyphae by regulating the dynamics of cytoplasmic microtubules in A spergillus nidulans
Author(s) -
Zeng Cui J. Tracy,
Kim HyeRyun,
Vargas Arispuro Irasema,
Kim JungMi,
Huang AnChi,
Liu Bo
Publication year - 2014
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12792
Subject(s) - biology , hypha , microtubule , cytoplasm , microbiology and biotechnology , mutant , apex (geometry) , tip growth , fungal protein , organelle , cytoskeleton , anatomy , gene , botany , genetics , cell , pollen , pollination , pollen tube
Summary Cytoplasmic microtubules ( MTs ) serve as a rate‐limiting factor for hyphal tip growth in the filamentous fungus A spergillus nidulans . We hypothesized that this function depended on the MT plus end‐tracking proteins (+ TIPs ) including the EB1 family protein EBA that decorated the MT plus ends undergoing polymerization. The ebA Δ mutation reduced colony growth and the mutant hyphae appeared in an undulating pattern instead of exhibiting unidirectional growth in the control. These phenotypes were enhanced by a mutation in another + TIP gene clipA . EBA was required for plus end‐tracking of CLIPA , the K inesin‐7 motor KipA , and the XMAP215 homologue AlpA . In addition, cytoplasmic dynein also depended on EBA to track on most polymerizing MT plus ends, but not for its conspicuous appearance at the MT ends near the hyphal apex. The loss of EBA reduced the number of cytoplasmic MTs and prolonged dwelling times for MTs after reaching the hyphal apex. Finally, we found that colonies were formed in the absence of EBA , CLIPA , and NUDA together, suggesting that they were dispensable for fundamental functions of MTs . This study provided a comprehensive delineation of the relationship among different + TIPs and their contributions to MT dynamics and unidirectional hyphal expansion in filamentous fungi.