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Dynamic distribution of BIMG PP1 in living hyphae of Aspergillus indicates a novel role in septum formation
Author(s) -
Fox H.,
Hickey P. C.,
FernándezÁbalos J. M.,
Lunness P.,
Read N. D.,
Doonan J. H.
Publication year - 2002
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 - 10.1046/j.1365-2958.2002.03092.x
Subject(s) - biology , nucleoplasm , green fluorescent protein , hypha , mitosis , microbiology and biotechnology , aspergillus nidulans , nucleolus , phosphatase , cell cycle , spindle pole body , cell division , nucleus , cell , botany , spindle apparatus , gene , biochemistry , phosphorylation , mutant
Summary Mutation of bim G, the major protein phosphatase 1 gene in Aspergillus nidulans , causes multiple cell cycle and hyphal growth defects that are associated with overphosphorylation of subcellular components. We have used functional translational fusions with the green fluorescent protein (GFP) to show that BIMG has at least four discrete locations within growing hyphae. Three of these locations, the hyphal tip, the spindle pole body and the nucleus, correlate with previously known requirements for bim G PP1 in mitosis and hyphal growth and are highly dynamic. BIMG‐GFP in the hyphal tip seemed to be associated with the plasma membrane and formed a collar of fluorescence within the apical dome. The distribution of nuclear BIMG‐GFP varied depending on nutritional conditions; on poor medium, it concentrated more in the nucleolus than in the nucleoplasm, whereas on rich medium, it was more evenly distributed between the two nuclear regions. The association of BIMG‐GFP with developing septa was transient, and we present evidence that BIMG phosphatase plays a direct role in septum formation, distinct from its role in mitosis. We conclude that, by being physically present at several sites, the BIMG phosphatase has roles in multiple cellular processes.