The SONB(NUP98) nucleoporin interacts with the NIMA kinase in Aspergillus nidulans.
The Aspergillus nidulans NIMA kinase is essential for mitotic entry. At restrictive temperature, temperature-sensitive nimA alleles arrest in G2, before accumulation of NIMA in the nucleus. We performed a screen for extragenic suppressors of the nimA1 allele and isolated two cold-sensitive son (suppressor of nimA1) mutants. The sonA1 mutant encoded a nucleoporin that is a homolog of yeast Gle2/Rae1. We have now cloned SONB, a second nucleoporin genetically interacting with NIMA. sonB is essential and encodes a homolog of the human NUP98/NUP96 precursor. Similar to NUP98/NUP96, SONB(NUP98/NUP96) is autoproteolytically cleaved to generate SONB(NUP98) and SONB(NUP96). SONB(NUP98) localizes to the nuclear pore complex and contains a GLEBS domain (Gle2 binding sequence) that binds SONA(GLE2). A point mutation within the GLEBS domain of SONB1(NUP98) suppresses the temperature sensitivity of the nimA1 allele and compromises the physical interaction between SONA(GLE2) and SONB1(NUP98). The sonB1 mutation also causes sensitivity to hydroxyurea. We isolated the histone H2A-H2B gene pair as a copy-number suppressor of sonB1 cold sensitivity and hydroxyurea sensitivity. The data suggest that the nucleoporins SONA(GLE2) and SONB(NUP98) and the NIMA kinase interact and regulate nuclear accumulation of mitotic regulators to help promote mitosis.
De Souza
Colin P C
CP
Department of Molecular Genetics, Ohio State University, Columbus, Ohio 43210, USA.
Horn
Kevin P
KP
Masker
Kathryn
K
Osmani
Stephen A
SA
D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000201:enzymology / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D003080:Cold Temperature; D006657:Histones / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D000072380:NIMA-Related Kinase 1; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
D018797:Cell Cycle Proteins; D006657:Histones; D028861:Nuclear Pore Complex Proteins; C093350:nuclear pore complex protein 98; C000606914:NEK1 protein, human; D000072380:NIMA-Related Kinase 1; D017346:Protein Serine-Threonine Kinases