Aspergillus
 nidulans
 swoF
 Encodes an
 N
 -Myristoyl Transferase

Shaw, Brian D.; Momany, Cory; Momany, Michelle

doi:10.1128/ec.1.2.241-248.2002

Cited by 32 publications

(49 citation statements)

References 48 publications

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“…Multiple temperature-sensitive mutations affecting polarity establishment and maintenance have also been recovered in A. nidulans (29,40,53). Consistent with the results obtained with N. crassa, characterization of the affected genes has identified several functions whose involvement in hyphal morphogenesis was not previously suspected (43,44,64,65). Collectively, these systematic studies underscore the complexity of hyphal morphogenesis and emphasize several features that distinguish it from the well-characterized yeast model.…”

Section: Geneticssupporting

confidence: 83%

Polarisome Meets Spitzenkörper: Microscopy, Genetics, and Genomics Converge

et al. 2005

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7The impact of filamentous fungi on human welfare has never been greater. Fungi are acknowledged as the most economically devastating plant pathogens (1) and are attaining increasing notoriety for their ability to cause life-threatening infections in humans (57,71), and fungal products sustain a billiondollar manufacturing industry (70). The tools available to study filamentous fungi are more sophisticated than ever and include the complete annotated genome sequences of multiple filamentous fungi (12), resources being made available through various functional genomics projects, and advanced bioimaging methods, including high-resolution live-cell imaging (20, 32) and electron tomography (19,50). The increasing impact of filamentous fungi, along with the rediscovery of pseudohyphal growth in yeast (22), has focused attention on the molecular mechanisms underlying hyphal morphogenesis.Attempts to understand hyphal morphogenesis have historically followed two different lines of investigation. Microscopists have defined, with increasing detail, the subcellular organization of the hyphal tip. This led to the description of the Spitzenkörper, an apical cluster of vesicles, cytoskeletal elements, and other proteins, which plays a crucial role in hyphal extension (4). Geneticists have identified gene products required for hyphal morphogenesis by characterizing morphological mutants (51,52). Initial studies in the laboratories of Beadle, Tatum, and colleagues attempted to link morphogenesis to specific biochemical pathways. More recent screens have identified a multitude of signaling and cytoskeletal functions required for hyphal extension (62, 72).In the past few years, comparative genomics efforts have allowed fungal biologists interested in hyphal morphogenesis to exploit the wealth of knowledge about polarized growth in the yeast Saccharomyces cerevisiae. Many informative homologies between filamentous fungi and yeast have been uncovered. Notably, this includes several components of a multiprotein complex termed the polarisome (28), which regulates microfilament formation at polarized growth sites in yeast (61).Perhaps more importantly, several gene products involved in hyphal morphogenesis have been shown to have no homologue outside of the filamentous fungi. This emphasizes the potential novelty of the mechanisms underlying hyphal morphogenesis. In this review, we summarize past efforts to understand hyphal morphogenesis and pose a series of questions designed to focus future efforts in this area. HYPHAL MORPHOGENESIS: A BRIEF OVERVIEWFungal hyphae originate from either a germinating spore or another hypha (i.e., during branch formation). Initially, an axis of polarity is established from a symmetrically expanding spore or hyphal compartment. Subsequently, cell surface expansion is restricted to the specified axis, thereby leading to the formation of a polarized hypha that displays a gradient of expansion that peaks at the tip (2,15,25,30,52). Maintenance of the polarity axis allows hyphae to achieve a linear extens...

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Section: Geneticssupporting

confidence: 83%

Polarisome Meets Spitzenkörper: Microscopy, Genetics, and Genomics Converge

et al. 2005

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“…We show here that MYR, like prenylation, is essential for various plant development processes and that a very small number of proteins of the N-myristoylome directly link MYR with one of these processes: SnRK1 kinase dysfunction and SAM development. In the filamentous fungus A. nidulans, a point mutation in an NMT gene reducing the affinity of myristoylCoA for NMT induces aberrant cell polarity (Shaw et al, 2002). Recently, a target of this mechanism during cell morphogenesis was proposed to correspond to the 26S proteosome (Lee and Shaw, 2007).…”

Section: Discussionmentioning

confidence: 99%

N-Myristoylation Regulates the SnRK1 Pathway inArabidopsis

et al. 2007

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Cotranslational and posttranslational modifications are increasingly recognized as important in the regulation of numerous essential cellular functions. N-myristoylation is a lipid modification ensuring the proper function and intracellular trafficking of proteins involved in many signaling pathways. Arabidopsis thaliana, like human, has two tightly regulated N-myristoyltransferase (NMT) genes, NMT1 and NMT2. Characterization of knockout mutants showed that NMT1 was strictly required for plant viability, whereas NMT2 accelerated flowering. NMT1 impairment induced extremely severe defects in the shoot apical meristem during embryonic development, causing growth arrest after germination. A transgenic plant line with an inducible NMT1 gene demonstrated that NMT1 expression had further effects at later stages. NMT2 did not compensate for NMT1 in the nmt1-1 mutant, but NMT2 overexpression resulted in shoot and root meristem abnormalities. Various data from complementation experiments in the nmt1-1 background, using either yeast or human NMTs, demonstrated a functional link between the developmental arrest of nmt1-1 mutants and the myristoylation state of an extremely small set of protein targets. We show here that protein N-myristoylation is systematically associated with shoot meristem development and that SnRK1 (for SNF1-related kinase) is one of its essential primary targets.

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“…pArfBTn2, carrying the transposon in the first predicted intron of the arfB (after 139 bp from the start of the gene) in the vector pGEM-arfB, was linearized with SphI (New England Biolabs Inc., Ipswich, MA), which cuts the plasmid outside of the arfB gene. The linearized plasmid was transformed using previously described methods (43) into A. nidulans strain TN02A7 (Table 1). This strain is disrupted at nkuA to enhance homologous recombination (37).…”

Section: Methodsmentioning

confidence: 99%

“…Shaw et al reported that a temperature-sensitive N-myristoyl transferase (NMT) mutant displayed a polarity maintenance defect in Aspergillus nidulans (43). Myristate from myristoyl-coenzyme A (CoA) is covalently attached to the secondary glycine of target proteins by NMT increasing in hydrophobicity (24).…”

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confidence: 99%

Aspergillus nidulans ArfB Plays a Role in Endocytosis and Polarized Growth

et al. 2008

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Filamentous fungi undergo polarized growth throughout most of their life cycles. The Spitzenkörper is an apical organelle composed primarily of vesicles that is unique to filamentous fungi and is likely to act as a vesicle supply center for tip growth. Vesicle assembly and trafficking are therefore important for hyphal growth. ADP ribosylation factors (Arfs), a group of small GTPase proteins, play an important role in nucleating vesicle assembly. Little is known about the role of Arfs in filamentous hyphal growth. We found that Aspergillus nidulans is predicted to encode six Arf family proteins. Analysis of protein sequence alignments suggests that A. nidulans ArfB shares similarity with ARF6 of Homo sapiens and Arf3p of Saccharomyces cerevisiae. An arfB null allele (arfB disrupted by a transposon [arfB::Tn]) was characterized by extended isotropic growth of germinating conidia followed by cell lysis or multiple, random germ tube emergence, consistent with a failure to establish polarity. The mutant germ tubes and hyphae that do form initially meander abnormally off of the axis of polarity and frequently exhibit dichotomous branching at cell apices, consistent with a defect in polarity maintenance. FM4-64 staining of the arfB::Tn strain revealed that another phenotypic characteristic seen for arfB::Tn is a reduction and delay in endocytosis. ArfB is myristoylated at its N terminus. Green fluorescent protein-tagged ArfB (ArfB::GFP) localizes to the plasma membrane and endomembranes and mutation (ArfB G2A ::GFP) of the N-terminal myristoylation motif disperses the protein to the cytoplasm rather than to the membranes. These results demonstrate that ArfB functions in endocytosis to play important roles in polarity establishment during isotropic growth and polarity maintenance during hyphal extension.

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Aspergillus nidulans swoF Encodes an N -Myristoyl Transferase

Cited by 32 publications

References 48 publications

Polarisome Meets Spitzenkörper: Microscopy, Genetics, and Genomics Converge

Polarisome Meets Spitzenkörper: Microscopy, Genetics, and Genomics Converge

N-Myristoylation Regulates the SnRK1 Pathway inArabidopsis

Aspergillus nidulans ArfB Plays a Role in Endocytosis and Polarized Growth

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