TY - JOUR
T1 - Copy number suppressors of the Aspergillus nidulans nimA1 mitotic kinase display distinctive and highly dynamic cell cycle-regulated locations
AU - Ukil, Leena
AU - Varadaraj, Archana
AU - Govindaraghavan, Meera
AU - Liu, Hui Lin
AU - Osmani, Stephen A.
PY - 2008/12
Y1 - 2008/12
N2 - The Aspergillus nidulans NIMA kinase is essential for mitosis and is the founding member of the conserved NIMA-related kinase (Nek) family of protein kinases. To gain insight into NIMA function, a copy number suppression screen has been completed that defines three proteins termed MCNA, MCNB, and MCNC (multi-copy-number suppressor of nimA1 A, B, and C). All display a distinctive and dynamic cell cycle-specific distribution. MCNC has weak similarity to Saccharomyces cerevisiae Def1 within a shared CUE-like domain. MCNC, like Def1, is a cytoplasmic protein with slow mobility during sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its deletion causes polarization defects and a small colony phenotype. MCNC enters nuclei during mitosis. In contrast, MCNB is a nuclear protein displaying increased nuclear levels as cells progress through interphase but is lost from nuclei at mitosis. MCNB is highly related to the Schizosaccharomyces pombe forkhead transcription factor Sep1 and is likely a transcriptional activator of nimA. Most surprisingly, MCNA, a protein restricted to the aspergilli and pathogenic systemic dimorphic fungi (the Eurotiomycetes), defines a nuclear body located near nucleoli at the nuclear periphery of G2 nuclei. During progression through mitosis, the MCNA body is excluded from nuclei. Cytoplasmic MCNA bodies then diminish during early stages of interphase, and single MCNA bodies are formed within nuclei as interphase progresses. Three sites of MCNA phosphorylation were mapped and mutated to implicate proline-directed phosphorylation in the equal segregation of MCNA during the cell cycle. The data indicate all three MCN proteins likely have cell cycle functions.
AB - The Aspergillus nidulans NIMA kinase is essential for mitosis and is the founding member of the conserved NIMA-related kinase (Nek) family of protein kinases. To gain insight into NIMA function, a copy number suppression screen has been completed that defines three proteins termed MCNA, MCNB, and MCNC (multi-copy-number suppressor of nimA1 A, B, and C). All display a distinctive and dynamic cell cycle-specific distribution. MCNC has weak similarity to Saccharomyces cerevisiae Def1 within a shared CUE-like domain. MCNC, like Def1, is a cytoplasmic protein with slow mobility during sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and its deletion causes polarization defects and a small colony phenotype. MCNC enters nuclei during mitosis. In contrast, MCNB is a nuclear protein displaying increased nuclear levels as cells progress through interphase but is lost from nuclei at mitosis. MCNB is highly related to the Schizosaccharomyces pombe forkhead transcription factor Sep1 and is likely a transcriptional activator of nimA. Most surprisingly, MCNA, a protein restricted to the aspergilli and pathogenic systemic dimorphic fungi (the Eurotiomycetes), defines a nuclear body located near nucleoli at the nuclear periphery of G2 nuclei. During progression through mitosis, the MCNA body is excluded from nuclei. Cytoplasmic MCNA bodies then diminish during early stages of interphase, and single MCNA bodies are formed within nuclei as interphase progresses. Three sites of MCNA phosphorylation were mapped and mutated to implicate proline-directed phosphorylation in the equal segregation of MCNA during the cell cycle. The data indicate all three MCN proteins likely have cell cycle functions.
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U2 - 10.1128/EC.00278-08
DO - 10.1128/EC.00278-08
M3 - Article
C2 - 18931041
AN - SCOPUS:57349118748
SN - 1535-9778
VL - 7
SP - 2087
EP - 2099
JO - Eukaryotic Cell
JF - Eukaryotic Cell
IS - 12
ER -