mbk-2 encodes one of two C. elegans members of the DYRK (dual-specificity Yak1-related kinase) family of proteins that includes S. cerevisiae Yak1 and the Drosophila minibrain and DYRK2 kinases; MBK-2 activity is required maternally for the oocyte-to-egg transition that occurs during the earliest stages of embryonic development; specifically, MBK-2 is required for: 1) posterior localization of the germ plasm components PIE-1, POS-1, and PGL-1, and 2) post-fertilization degradation of a subset of maternal proteins including the MEI-1 and MEI-2 meiosis-specific katanin subunits, the OMA-1 oocyte maturation factor, and residual PIE-1 that remains anteriorly localized after its normal posterior segregation; MBK-2 also primes the MEX-5 polarity protein for subsequent phosphorylation by the polo-like kinase PLK-1; genetic analyses suggest that, in regulating the segregation and degradation of maternal proteins, MBK-2 lies downstream of the initial embryonic polarity cues established by the PAR and MEX proteins; MBK-2 activity depends upon progression through the meiotic divisions and is positively regulated by CDK-1 and negatively regulated by EGG-3 and EGG-4/5; MBK-2 physically interacts with EGG-3 and EGG-4, suggesting that regulation by EGG-3 and EGG-4 is direct; MBK-2 is expressed uniformly in the cortex of oocytes and newly fertilized zygotes; in later stage zygotes, just prior to the second meiotic division, MBK-2 becomes localized to discrete cortical foci, and by the first mitosis it is found predominantly on centrosomes and chromosomes; MBK-2 is also associated with P granules in the germline blastomeres P2, P3, and P4.
Enables protein serine/threonine kinase activity and protein tyrosine kinase activity. Involved in several processes, including P granule disassembly; asymmetric protein localization involved in cell fate determination; and positive regulation of proteasomal ubiquitin-dependent protein catabolic process. Located in cell cortex and intracellular non-membrane-bounded organelle. Expressed in several structures, including body wall musculature; embryonic cell; gonad; oocyte; and pharynx. Used to study Down syndrome. Is an ortholog of human DYRK2 (dual specificity tyrosine phosphorylation regulated kinase 2) and DYRK3 (dual specificity tyrosine phosphorylation regulated kinase 3).
Human DYRK1A gene encodes a member of the dual-specificity tyrosine phosphorylation-regulated kinase (DYRK) family, which includes Drosophila minibrain, and is a conserved gene located in the Down Syndrome critical region (DSCR) of chromosome 21; Down syndrome is the most frequent chromosomal abnormality in human infants, where DYRK1A overexpression is observed, and is characterized by a set of facial and physical features, heart defects, abnormalities in the immune and endocrine systems, spatial memory defecits and difficulty in converting short-term to long-term memories; in elegans, the genes mbk-1 and mbk-2 have close homology with human DYRK1A and hpk-1 is more distantly related; while mutants deficient for mbk-1 seem to be normal, overexpression of mbk-1 causes behavioral defects in chemotaxis, acting in mature, fully differentiated neurons; however, this defect could be reversed by bringing back normal mbk-1 levels, which provided the first hint that DYRK1-induced defects could be reversed; mbk-2(pk1427) homozygous animals display 100% penetrant maternal-effect embryonic lethality, making it difficult to test redundant function with mbk-1.
Sequence connection from [Raich WB]. 02/06/12 krb.
Map position created from combination of previous interpolated map position (based on known location of sequence) and allele information. Therefore this is not a genetic map position based on recombination frequencies or genetic experiments. This was done on advice of the CGC.