Abstract
It has been demonstrated that Saccharomyces cerevisiae Vam6p/Vps39p plays a critical role in the tethering steps of vacuolar membrane fusion by facilitating guanine nucleotide exchange on small guanosine triphosphatase (GTPase) Vam4p/Ypt7p. We report here the identification and characterization of a novel protein in Aspergillus nidulans, AvaB, that exhibits similarity to Vam6p/Vps39p and plays a critical role in vacuolar morphogenesis in A. nidulans. AvaB is comprised of 1058 amino acids with amino-terminal citron homology (CNH) and central clathrin homology (CLH) domains, as observed for other Vam6p/Vps39p family proteins. Disruption of avaB in A. nidulans resulted in the fragmentation of vacuoles and reduced growth rate under various growth conditions, implying its importance in maintaining vacuolar morphology and function. Yeast two-hybrid analysis demonstrated the interaction of AvaB with AvaA, a Vam4p/Ypt7p homolog in A. nidulans, as well as the homooligomer formation of AvaB, suggesting that AvaB performs its function through hetero- or homophilic protein-protein interactions.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Vesicular Transport
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Amino Acid Sequence
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Aspergillus nidulans / cytology
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Aspergillus nidulans / genetics*
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Aspergillus nidulans / growth & development
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Aspergillus nidulans / physiology
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Base Sequence
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Cell Cycle Proteins / genetics
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Clathrin / genetics
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Cloning, Molecular
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DNA, Fungal / chemistry
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DNA, Fungal / isolation & purification
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Fungal Proteins / chemistry
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Fungal Proteins / genetics*
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Fungal Proteins / physiology*
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Genes, Fungal*
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Introns / genetics
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Membrane Proteins / chemistry
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Membrane Proteins / genetics
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Membrane Proteins / physiology
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Molecular Sequence Data
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Mutagenesis, Insertional
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Protein Binding
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Protein Structure, Quaternary
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Protein Structure, Tertiary
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Saccharomyces cerevisiae Proteins*
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Sequence Analysis, DNA
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Sequence Homology
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Two-Hybrid System Techniques
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Vacuoles / metabolism
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Vacuoles / ultrastructure
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rab GTP-Binding Proteins / genetics
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rab GTP-Binding Proteins / physiology
Substances
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Adaptor Proteins, Vesicular Transport
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Cell Cycle Proteins
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Clathrin
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DNA, Fungal
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Fungal Proteins
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Membrane Proteins
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Saccharomyces cerevisiae Proteins
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VAM6 protein, S cerevisiae
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YPT7 protein, S cerevisiae
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rab GTP-Binding Proteins