Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.4.4 (kinesin)
 5,033 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytokinesis is the critical step during which daughter cells are separated. We showed previously that a protein complex that consists of NACK1 (and NACK2) kinesin-like protein and NPK1 MAPKKK and its substrate NQK1 MAPKK are required for progression of cytokinesis in Nicotiana tabacum. The genome of Arabidopsis thaliana encodes homologues of NACK1 and NACK2, namely, AtNACK1/HINKEL and STUD/TETRASPORE/AtNACK2, respectively. Loss-of-function mutations in AtNACK1/HINKEL and STUD/TETRASPORE/AtNACK2 result in the occasional failure of somatic and male-meiotic cytokinesis, respectively. However, it is likely that these genes function redundantly to some extent in somatic tissues and female gametogenesis. We describe the phenotypes of Arabidopsis plants that have mutations in both the AtNACK1/HINKEL and STUD/TETRASPORE/AtNACK2 genes. These phenotypes suggest that the two genes are essential during both male and female gametogenesis. Female gametes with atnack1 atnack2 double mutations failed to cellularize and to generate a central cell, synergids and the egg cells. Male gametes with atnack1 atnack2 mutations were also not transmitted to the next generation. The AtNACK1/HINKEL and STUD/TETRASPORE/AtNACK2 genes for kinesin-like proteins have overlapping functions that are essential for gametogenetic cytokinesis. They appear to be essential components of a MAP kinase cascade that promotes cytokinesis of plant cells in both gametophytic (haploid) and sporophytic (diploid) proliferation.
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PMID:The AtNACK1/HINKEL and STUD/TETRASPORE/AtNACK2 genes, which encode functionally redundant kinesins, are essential for cytokinesis in Arabidopsis. 1556 52

The NACK kinesins (NACK1, NACK2 in tobacco and AtNACK1/HINKEL, AtNACK2/STUD/TETRASPORE in Arabidopsis), members of a plant-specific kinesin-7 family, are required for cytokinesis. Previous studies using tobacco and Arabidopsis cells showed that NACK1 and AtNACK1 at the phragmoplast midzone activate the MAP kinase cascade during the late M phase, which is critical for the cell plate formation. However, the loss-of-function phenotype has not been investigated in details in living cells and the molecular activity of this kinesin remains to be determined. Here, we report the mitotic roles and activity of the NACK kinesins in the moss Physcomitrella patens. When we simultaneously knocked down three PpNACKs by RNA-interference (RNAi) in protonemal cells, we observed a cytokinesis failure following a defect in phragmoplast expansion. In addition, misaligned chromosomes were frequently detected in the pre-anaphase spindle and the anaphase onset was significantly delayed, indicating that PpNACK also plays a role in pre-anaphase. Consistent with the appearance of early and late mitotic phenotypes, endogenous PpNACK was localised to the interpolar microtubule (MT) overlap from prometaphase through telophase. In vitro MT gliding assay and single motor motility assay showed that PpNACK-b is a processive, plus-end-directed motor, suggesting that PpNACK is capable of transporting cargoes along the spindle/phragmoplast MT. Our study using Physcomitrella patens demonstrated that PpNACK is an active motor protein and identified unexpected and conserved roles of PpNACK during the mitosis of P. patens.
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PMID:NACK kinesin is required for metaphase chromosome alignment and cytokinesis in the moss Physcomitrella patens. 2574 59