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Vasselli JG, Kainer E, Shaw BD. Using fimbrin to quantify the endocytic subapical collar during polarized growth in three filamentous fungi. Mycologia 2023:1-14. [PMID: 37196171 DOI: 10.1080/00275514.2023.2202689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 04/09/2023] [Indexed: 05/19/2023]
Abstract
Filamentous fungi produce specialized cells called hyphae. These cells grow by polarized extension at their apex, which is maintained by the balance of endocytosis and exocytosis at the apex. Although endocytosis has been well characterized in other organisms, the details of endocytosis and its role in maintaining polarity during hyphal growth in filamentous fungi is comparatively sparsely studied. In recent years, a concentrated region of protein activity that trails the growing apex of hyphal cells has been discovered. This region, dubbed the "endocytic collar" (EC), is a dynamic 3-dimensional region of concentrated endocytic activity, the disruption of which results in the loss of hyphal polarity. Here, fluorescent protein-tagged fimbrin was used as a marker to map the collar during growth of hyphae in three fungi: Aspergillus nidulans, Colletotrichum graminicola, and Neurospora crassa. Advanced microscopy techniques and novel quantification strategies were then utilized to quantify the spatiotemporal localization and recovery rates of fimbrin in the EC during hyphal growth. Correlating these variables with hyphal growth rate revealed that the strongest observed relationship with hyphal growth is the distance by which the EC trails the apex, and that measured endocytic rate does not correlate strongly with hyphal growth rate. This supports the hypothesis that endocytic influence on hyphal growth rate is better explained by spatiotemporal regulation of the EC than by the raw rate of endocytosis.
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Affiliation(s)
- Joseph G Vasselli
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas 77843
| | - Ellen Kainer
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas 77843
| | - Brian D Shaw
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, Texas 77843
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Jin J, Iwama R, Takagi K, Horiuchi H. AP-2 complex contributes to hyphal-tip-localization of a chitin synthase in the filamentous fungus Aspergillus nidulans. Fungal Biol 2021; 125:806-814. [PMID: 34537176 DOI: 10.1016/j.funbio.2021.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/06/2021] [Accepted: 05/18/2021] [Indexed: 10/20/2022]
Abstract
Filamentous fungi maintain hyphal growth to continually internalize membrane proteins related to cell wall synthesis, transporting them to the hyphal tips. Endocytosis mediates protein internalization via target recognition by the adaptor protein 2 complex (AP-2 complex). The AP-2 complex specifically promotes the internalization of proteins important for hyphal growth, and loss of AP-2 complex function results in abnormal hyphal growth. In this study, deletion mutants of the genes encoding the subunits of the AP-2 complex (α, β2, μ2, or σ2) in the filamentous fungus Aspergillus nidulans resulted in the formation of conidiophores with abnormal morphology, fewer conidia, and activated the cell wall integrity pathway. We also investigated the localization of ChsB, which plays pivotal roles in hyphal growth in A. nidulans, in the Δμ2 strain. Quantitative analysis suggested that the AP-2 complex is involved in ChsB internalization at subapical collar regions. The absence of the AP-2 complex reduced ChsB localization at the hyphal tips. Our findings suggest that the AP-2 complex contributes to cell wall integrity by properly localizing ChsB to the hyphal tips.
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Affiliation(s)
- Jingyun Jin
- Department of Biotechnology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Ryo Iwama
- Department of Biotechnology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan; Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Keiko Takagi
- Department of Biotechnology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Hiroyuki Horiuchi
- Department of Biotechnology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan; Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan.
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Higuchi Y. Membrane traffic related to endosome dynamics and protein secretion in filamentous fungi. Biosci Biotechnol Biochem 2021; 85:1038-1045. [PMID: 33686391 DOI: 10.1093/bbb/zbab004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/29/2020] [Indexed: 12/27/2022]
Abstract
In eukaryotic cells, membrane-surrounded organelles are orchestrally organized spatiotemporally under environmental situations. Among such organelles, vesicular transports and membrane contacts occur to communicate each other, so-called membrane traffic. Filamentous fungal cells are highly polarized and thus membrane traffic is developed to have versatile functions. Early endosome (EE) is an endocytic organelle that dynamically exhibits constant long-range motility through the hyphal cell, which is proven to have physiological roles, such as other organelle distribution and signal transduction. Since filamentous fungal cells are also considered as cell factories, to produce valuable proteins extracellularly, molecular mechanisms of secretory pathway including protein glycosylation have been well investigated. In this review, molecular and physiological aspects of membrane traffic especially related to EE dynamics and protein secretion in filamentous fungi are summarized, and perspectives for application are also described.
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Affiliation(s)
- Yujiro Higuchi
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
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Caesar LK, Kelleher NL, Keller NP. In the fungus where it happens: History and future propelling Aspergillus nidulans as the archetype of natural products research. Fungal Genet Biol 2020; 144:103477. [PMID: 33035657 DOI: 10.1016/j.fgb.2020.103477] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/21/2020] [Accepted: 09/30/2020] [Indexed: 02/08/2023]
Abstract
In 1990 the first fungal secondary metabolite biosynthetic gene was cloned in Aspergillus nidulans. Thirty years later, >30 biosynthetic gene clusters (BGCs) have been linked to specific natural products in this one fungal species. While impressive, over half of the BGCs in A. nidulans remain uncharacterized and their compounds structurally and functionally unknown. Here, we provide a comprehensive review of past advances that have enabled A. nidulans to rise to its current status as a natural product powerhouse focusing on the discovery and annotation of secondary metabolite clusters. From genome sequencing, heterologous expression, and metabolomics to CRISPR and epigenetic manipulations, we present a guided tour through the evolution of technologies developed and utilized in the last 30 years. These insights provide perspective to future efforts to fully unlock the biosynthetic potential of A. nidulans and, by extension, the potential of other filamentous fungi.
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Affiliation(s)
- Lindsay K Caesar
- Department of Chemistry, Northwestern University, Evanston, IL, United States
| | - Neil L Kelleher
- Department of Chemistry, Northwestern University, Evanston, IL, United States; Department of Molecular Biosciences, Northwestern University, Evanston, IL, United States; Proteomics Center of Excellence, Northwestern University, Evanston, IL, United States
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin- Madison, Madison, WI, United States; Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, United States.
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