The minibrain kinase homolog, mbk-2, is required for spindle positioning and asymmetric cell division in early C. elegans embryos.
In the newly fertilized Caenorhabditis elegans zygote, cytoplasmic determinants become localized asymmetrically along the anterior-posterior (A-P) axis of the embryo. The mitotic apparatus then orients so as to cleave the embryo into anterior and posterior blastomeres that differ in both size and developmental potential. Here we describe a role for MBK-2, a member of the Dyrk family of protein kinases, in asymmetric cell division in C. elegans. In mbk-2 mutants, the initial mitotic spindle is misplaced and cytoplasmic factors, including the germline-specific protein PIE-1, are mislocalized. Our findings support a model in which MBK-2 down-regulates the katanin-related protein MEI-1 to control spindle positioning and acts through distinct, as yet unknown factors, to control the localization of cytoplasmic determinants. These findings in conjunction with work from Schizosaccharomyces pombe indicate a possible conserved role for Dyrk family kinases in the regulation of spindle placement during cell division.
Pang
Ka Ming
KM
Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Ishidate
Takao
T
Nakamura
Kuniaki
K
Shirayama
Masaki
M
Trzepacz
Chris
C
Schubert
Charlotte M
CM
Priess
James R
JR
Mello
Craig C
CC
D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000502:physiology; D029742:Caenorhabditis elegans Proteins / Q000502:physiology*; D002455:Cell Division / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D008941:Spindle Apparatus / Q000502:physiology*
D029742:Caenorhabditis elegans Proteins; D009687:Nuclear Proteins; C100950:pie-1 protein, C elegans; C478059:MBK-2 protein, C elegans; D011505:Protein-Tyrosine Kinases