Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Common to all eukaryotes, kinesins are cytoskeletal motor proteins that mediate intracellular transport on microtubule tracks, using ATP hydrolysis. A Caenorhabditis elegans cDNA clone corresponding to the klp-3 gene, encoding a novel kinesin, was isolated, and mapped on LGII. Northern blot analysis using the klp-3 cDNA probe reveals a 1.9 kb mRNA that is transcribed at a low level during development. Temporal and spatial expression of the klp-3::lacZ fusion gene is limited to the marginal cells in the pharynx, and a group of muscle cells in the posterior gut region. The nucleotide sequence of klp-3 has been deduced from the cDNA and nematode genome sequencing consortium data. Conceptual translation of the klp-3 gene reveals a kinesin-like protein with its conserved motor domain containing the ATP binding and microtubule binding sites located in the C terminus. KLP-3 shares extensive homology with the yeast Kar3 and Drosophila ncd kinesins, which have previously been shown to mediate chromosomal movement and segregation during meiosis and mitosis. Overexpression of the klp-3 gene partially rescues the lethal phenotype of the maternal lethal him-14 ts(it44) mutants at non-permissive temperatures, and reduces the incidence of males caused by non-disjunction of the X-chromosome. Similarly, expression of a klp-3 antisense RNA, under the control of a heat shock promoter, causes embryonic arrest, dead eggs and polyploid cells in transgenic lines, suggesting a critical role for the klp-3 function in chromosome segregation. Further analysis of the klp-3 gene in C. elegans may elucidate diverse functions of the C terminus mitotic motor proteins during development.
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PMID:Molecular cloning and expression of the Caenorhabditis elegans klp-3, an ortholog of C terminus motor kinesins Kar3 and ncd. 924 92

Members of the kinesin protein family transport intracellular cargo to their correct cellular destination. Previously we have characterized the klp-3 gene from Caenorhabditis elegans, which encodes an ortholog of the retrograde C-terminus kinesin motors, such as Drosophila NCD, and yeast KAR3, involved in the chromosomal movement. Here we report the cloning of a full-length klp-17 cDNA in C. elegans, encoding a C-terminus kinesin of 605 amino residues. KLP-17 sequence defines a novel phylogenetic group, distinct from the NCD/KAR3 family. Interestingly, the klp-17 gene transcript is restricted to the nuclear compartment, as deduced by the RNA in situ hybridization in embryos. The klp-17::gfp-expressing transgenic animals do not display any GFP fluorescence signal, but expression of the extra chromosomal arrays cause production of abnormal males, and embryos with morphological defects and lethality in the progeny. Similarly, the klp-17 RNA interference assay results in embryonic death, arrested embryos, and polyploid cells. Thus, KLP-17 represents a new motor protein that mediates chromosome movement, essential for cell divisions during metazoan development.
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PMID:cDNA cloning and expression of a C-terminus motor kinesin-like protein KLP-17, involved in chromosomal movement in Caenorhabditis elegans. 1063 Nov 16

C-terminal kinesin motor proteins, such as the Drosophila NCD and yeast KAR3, are involved in chromosomal segregation. Previously we have described two orthologs of NCD in Caenorhabditis elegans, KLP-3 and KLP-17, which also participate in chromosome movement. Here we report cDNA cloning of klp-15 and klp-16, and the expression pattern of the genes encoding C-terminal motor kinesins including klp-15 and klp-16. Interestingly KLP-15 and KLP-16 form a unique class of C-terminal kinesins, distinct from the previously known C-terminal motors in other organisms. Using in situ hybridization and RNA interference assay, we show that although all of these motors mediate chromosome segregation, they do so in a combination of unique and overlapping manners, suggesting a complex hierarchy of kinesin motor function in metazoans.
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PMID:A novel C-terminal kinesin subfamily may be involved in chromosomal movement in caenorhabditis elegans. 1072 48

The distal region of a short arm of chromosome 1p is frequently deleted in many human cancers including neuroblastoma (NBL), in which it has been narrowed down to the smallest region of overlap between D1S244 and D1S214 (approximately 7 cM). During the search for the candidate tumor suppressor genes mapped within the region, we found the KIAA0591 gene which encoded a new human kinesin-related protein with a homology to human axonal transporter of synaptic vesicles (ATSV). The kinesin is an intracellular motor protein and often associated with neuronal differentiation and survival. Here we identified a complete open reading frame of the KIAA0591 gene by screening a cDNA library derived from human substantia nigra. The KIAA0591 protein contains a possible pleckstrin homology (PH) domain at its carboxy-terminus. However, it did not possess a force-generating motor domain which is well conserved among kinesin superfamily members (KIFs). Northern blot analysis demonstrated that KIAA0591 mRNA was preferentially expressed in both adult and fetal brains, kidney, skeletal muscle and pancreas. KIAA0591 was expressed in favorable NBLs at higher levels than in unfavorable NBLs, although RT-PCR SSCP analysis showed no mutation within the coding region of the KIAA0591 gene, when 8 neuroblastoma tissues and 15 neuroblastoma-derived cell lines were examined. Thus, the full-length KIAA0591 gene may be a novel member of human KIF superfamily which lacks motor domain and might function as a tumor suppressor in an epigenetic but not a classic Knudson's manner.
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PMID:Identification of the full-length KIAA0591 gene encoding a novel kinesin-related protein which is mapped to the neuroblastoma suppressor gene locus at 1p36.2. 1076 26

Kinesins are intracellular multimeric transport motor proteins that move cellular cargo on microtubule tracks. It has been shown that the sea urchin KRP85/95 holoenzyme associates with a KAP115 non-motor protein, forming a heterotrimeric complex in vitro, called the Kinesin-II. Here we describe isolation of a cDNA clone corresponding to the klp-11 kinesin in C. elegans. Our sequence analysis of the encoded KLP-11 shows that it shares high homology with the OSM-3 kinesin. We also describe a nematode cDNA encoding KAP-1 that shares extensive homology with the sea urchin KAP115 kinesin associated protein. Sequence-based structural analysis of the OSM-3, KLP-11, and KAP-1, presented here suggests that these may form a heterotrimeric complex. We also describe the presence of a Drosophila armadillo consensus motif in CeKAP-1, first found in spKAP115, that suggests a possible role for the KAP-1 in signal transduction.
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PMID:C. elegans KLP-11/OSM-3/KAP-1: orthologs of the sea urchin kinesin-II, and mouse KIF3A/KIFB/KAP3 kinesin complexes. 1081 27

The proper segregation of chromosomes during meiosis or mitosis requires the assembly of well organized spindles. In many organisms, meiotic spindles lack centrosomes. The formation of such acentrosomal spindles seems to involve first assembly or capture of microtubules (MTs) in a random pattern around the meiotic chromosomes and then parallel bundling and bipolar organization by the action of MT motors and other proteins. Here, we describe the structure, distribution, and function of KLP-18, a Caenorhabditis elegans Klp2 kinesin. Previous reports of Klp2 kinesins agree that it concentrates in spindles, but do not provide a clear view of its function. During prometaphase, metaphase, and anaphase, KLP-18 concentrates toward the poles in both meiotic and mitotic spindles. Depletion of KLP-18 by RNA-mediated interference prevents parallel bundling/bipolar organization of the MTs that accumulate around female meiotic chromosomes. Hence, meiotic chromosome segregation fails, leading to haploid or aneuploid embryos. Subsequent assembly and function of centrosomal mitotic spindles is normal except when aberrant maternal chromatin is present. This suggests that although KLP-18 is critical for organizing chromosome-derived MTs into a parallel bipolar spindle, the order inherent in centrosome-derived astral MT arrays greatly reduces or eliminates the need for KLP-18 organizing activity in mitotic spindles.
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PMID:KLP-18, a Klp2 kinesin, is required for assembly of acentrosomal meiotic spindles in Caenorhabditis elegans. 1293 78

Kinesins form a superfamily of molecular motors involved in cell division and intracellular transport. Twenty kinesins have been found in the Caenorhabditis elegans genome, and four of these belong to the kinesin-14 subfamily, i.e., kinesins with C-terminal motor domains. Three of these kinesin-14s, KLP-15, KLP-16, and KLP-17, form a distinct subgroup in which KLP-15 and KLP-16 are more than 90% identical and appear to be related by a relatively recent gene duplication. They are essential for meiotic spindle organization and chromosome segregation, and are mostly expressed in the germline. With 587 amino acids each, they are among the smallest kinesins known. Using bacterially expressed KLP-15 constructs with different length extensions preceding the motor domain, we have determined in vitro the following characteristic properties: ATPase activity, microtubule binding, oligomeric state, microtubule gliding activity, and direction of movement. The constructs exhibit a monomer-dimer equilibrium that depends on the length of the predicted alpha-helical coiled-coil region preceding the motor domain. The longest construct with the complete coiled-coil domain is a stable dimer, and the shortest construct with only seven amino acids preceding the motor domain is a monomer. In microtubule gliding assays, the monomer is immobile whereas the fully dimeric KLP-15 construct supports gliding at 2.3 microm/min and moves toward microtubule minus ends, like other members of the kinesin-14 subfamily studied to date.
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PMID:Essential kinesins: characterization of Caenorhabditis elegans KLP-15. 1585 Mar 86

We provide here the first evidence that a distinct midzone is present in the Drosophila melanogaster female meiosis I spindle. This region has the ability to bind the Pavarotti kinesin-like (PAV-KLP) and Abnormal spindle (Asp) proteins, indicating a correct organization of the central spindle microtubules. We also identified the core component centrosomal protein centrosomin (CNN) at an unexpected site within the anaphase I spindle, indicating a role for CNN during the biogenesis of the female meiotic apparatus. However, there are no apparent defects in the midzone organization of cnn oocytes, whereas defects occur later when the central aster forms. The primary mutant phenotype of cnn oocytes is the failure to form a developed central microtubule organizing center (MTOC), although twin meiosis II spindles usually do form. Thus the central MTOC may not be essential for the formation of the inner poles of twin meiosis II spindles, as generally proposed, but it might be involved in maintaining their proper spacing. We discuss the proposal that, in the presence of a central MTOC, a chromatin-driven mechanism of spindle assembly like that described during meiosis I may control the morphogenesis of the twin meiosis II spindles.
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PMID:The meiotic spindle of the Drosophila oocyte: the role of centrosomin and the central aster. 1597 43

Microtubules (MTs) are dynamic polymers that undergo cell cycle and position-sensitive regulation of polymerization and depolymerization. Although many different factors that regulate MT dynamics have been described, to date there has been no systematic analysis of genes required for MT dynamics in a single system. Here, we use a transgenic EB1::GFP strain, which labels the growing plus ends of MTs, to analyze the growth rate, nucleation rate, and distribution of growing MTs in the Caenorhabditis elegans embryo. We also present the results from an RNAi screen of 40 genes previously implicated in MT-based processes. Our findings suggest that fast microtubule growth is dependent on the amount of free tubulin and the ZYG-9-TAC-1 complex. Robust MT nucleation by centrosomes requires AIR-1, SPD-2, SPD-5, and gamma-tubulin. However, we found that centrosomes do not nucleate MTs to saturation; rather, the depolymerizing kinesin-13 subfamily member KLP-7 is required to limit microtubule outgrowth from centrosomes.
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PMID:Identification and characterization of factors required for microtubule growth and nucleation in the early C. elegans embryo. 1605 29

The TRP (transient receptor potential) superfamily of cation channels is present in all eukaryotes, from yeast to mammals. Many TRP channels have been studied in the nematode Caenorhabditis elegans, revealing novel biological functions, regulatory modes, and mechanisms of localization. C. elegans TRPV channels function in olfaction, mechanosensation, osmosensation, and activity-dependent gene regulation. Their activity is regulated by G protein signaling and polyunsaturated fatty acids. C. elegans TRPPs related to human polycystic kidney disease genes are expressed in male-specific neurons. The KLP-6 kinesin directs TRPP channels to cilia, where they may interact with F0/F1 ATPases. A sperm-specific TRPC channel, TRP-3, is required for fertilization. Upon sperm activation, TRP-3 translocates from an intracellular compartment to the plasma membrane to allow store-operated Ca2+ entry. The TRPM channels GON-2 and GTL-2 regulate Mg2+ homeostasis and Mg2+ uptake by intestinal cells; GON-2 is also required for gonad development. The TRPML CUP-5 promotes normal lysosome biogenesis and prevents apoptosis. Dynamic, precise expression of TRP proteins generates a remarkable range of cellular functions.
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PMID:TRP channels in C. elegans. 1646 Feb 89


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