Where to grow and where to go

Area of Science:

• Cell Biology
• Mycology
• Biochemistry

Background:

• Filamentous fungi elongate via membrane and cell-wall synthesis, relying on vesicle transport along microtubules and actin cables.
• The precise mechanisms defining fungal growth zones and vesicle fusion sites are not fully understood.
• Cell-end marker proteins (CEMPs) are implicated in establishing and maintaining cellular polarity.

Purpose of the Study:

• To investigate the role of CEMPs in fungal polarity maintenance and growth.
• To explore the coordination between microtubule and actin cytoskeletons mediated by CEMPs.
• To understand the impact of CEMP function and dysfunction on fungal morphology.

Main Methods:

• Studies on model fungi like Schizosaccharomyces pombe and Aspergillus nidulans.
• Analysis of CEMP-coding gene deletion mutants and overexpression strains.
• Phenotypic analysis of fungal growth and structure, including trapping structures in Arthrobotrys flagrans.

Main Results:

• CEMPs coordinate microtubule and actin cytoskeletons, forming multi-protein complexes with formin.
• CEMP-deficient mutants exhibit altered growth, such as T-shaped cells in S. pombe and less straight germlings in A. nidulans.
• CEMP mutants in Arthrobotrys flagrans show a severe defect in forming adhesive rings, producing sticks instead, while overexpression leads to hyperbranching.

Conclusions:

• CEMPs are crucial for polarity maintenance and play critical roles in modulating polarity during fungal development.
• The study highlights the differential importance of CEMPs across fungal species, with significant roles in specialized structures.
• CEMPs act as key regulators linking cytoskeletal dynamics to directed cell growth in fungi.