-
Genes To Cells : Devoted To Molecular &... Jan 2024The c-Jun N-terminal kinase-associated leucine zipper protein (JLP), a scaffold protein of mitogen-activated protein kinase signaling pathways, is a multifunctional...
The c-Jun N-terminal kinase-associated leucine zipper protein (JLP), a scaffold protein of mitogen-activated protein kinase signaling pathways, is a multifunctional protein involved in a variety of cellular processes. It has been reported that JLP is overexpressed in various types of cancer and is expected to be a potential therapeutic target. However, whether and how JLP overexpression affects non-transformed cells remain unknown. Here, we aimed to investigate the effect of JLP overexpression on chromosomal stability in human non-transformed cells and the mechanisms involved. We found that aneuploidy was induced in JLP-overexpressed cells. Moreover, we established JLP-inducible cell lines and observed an increased frequency of chromosome missegregation, reduced time from nuclear envelope breakdown to anaphase onset, and decreased levels of the spindle assembly checkpoint (SAC) components at the prometaphase kinetochore in cells overexpressing the wild-type JLP. In contrast, we observed that a point mutant JLP lacking the ability to interact with dynein light intermediate chain 1 (DLIC1) failed to induce chromosomal instability. Our results suggest that overexpression of the wild-type JLP facilitates premature SAC silencing through interaction with DLIC1, leading to aneuploidy. This study provides a novel insight into the mechanism through which JLP overexpression is associated with cancer development and progression.
Topics: Humans; Adaptor Proteins, Signal Transducing; Leucine Zippers; Dyneins; Neoplasms; Chromosomal Instability; Aneuploidy; Mitosis
PubMed: 37963657
DOI: 10.1111/gtc.13083 -
Nature Communications Nov 2023Cytoplasmic dynein drives the motility and force generation functions towards the microtubule minus end. The assembly of dynein with dynactin and a cargo adaptor in an...
Cytoplasmic dynein drives the motility and force generation functions towards the microtubule minus end. The assembly of dynein with dynactin and a cargo adaptor in an active transport complex is facilitated by Lis1 and Nde1/Ndel1. Recent studies proposed that Lis1 relieves dynein from its autoinhibited conformation, but the physiological function of Nde1/Ndel1 remains elusive. Here, we investigate how human Nde1 and Lis1 regulate the assembly and subsequent motility of mammalian dynein using in vitro reconstitution and single molecule imaging. We find that Nde1 recruits Lis1 to autoinhibited dynein and promotes Lis1-mediated assembly of dynein-dynactin adaptor complexes. Nde1 can compete with the α2 subunit of platelet activator factor acetylhydrolase 1B (PAF-AH1B) for the binding of Lis1, which suggests that Nde1 may disrupt PAF-AH1B recruitment of Lis1 as a noncatalytic subunit, thus promoting Lis1 binding to dynein. Before the initiation of motility, the association of dynactin with dynein triggers the dissociation of Nde1 from dynein by competing against Nde1 binding to the dynein intermediate chain. Our results provide a mechanistic explanation for how Nde1 and Lis1 synergistically activate the dynein transport machinery.
Topics: Animals; Humans; Dyneins; Microtubule-Associated Proteins; Dynactin Complex; Microtubules; Cytoskeleton; 1-Alkyl-2-acetylglycerophosphocholine Esterase; Mammals
PubMed: 37940657
DOI: 10.1038/s41467-023-42907-x -
ELife Nov 2023Male infertility is common and complex, presenting a wide range of heterogeneous phenotypes. Although about 50% of cases are estimated to have a genetic component, the...
Male infertility is common and complex, presenting a wide range of heterogeneous phenotypes. Although about 50% of cases are estimated to have a genetic component, the underlying cause often remains undetermined. Here, from whole-exome sequencing on samples from 168 infertile men with asthenoteratozoospermia due to severe sperm flagellum, we identified homozygous variants in four unrelated patients. In sperm cells from these individuals, immunofluorescence revealed altered localization of DNAH1, DNALI1, WDR66, and TTC29. Axonemal localization of ZMYND12 ortholog TbTAX-1 was confirmed using the model. RNAi knock-down of TbTAX-1 dramatically affected flagellar motility, with a phenotype similar to the sperm from men bearing homozygous variants. Co-immunoprecipitation and ultrastructure expansion microscopy in revealed TbTAX-1 to form a complex with TTC29. Comparative proteomics with samples from and KO mice identified a third member of this complex: DNAH1. The data presented revealed that ZMYND12 is part of the same axonemal complex as TTC29 and DNAH1, which is critical for flagellum function and assembly in humans, and . ZMYND12 is thus a new asthenoteratozoospermia-associated gene, bi-allelic variants of which cause severe flagellum malformations and primary male infertility.
Topics: Humans; Male; Animals; Mice; Asthenozoospermia; Semen; Flagella; Infertility, Male; Fertility; Calcium-Binding Proteins; Dyneins
PubMed: 37934199
DOI: 10.7554/eLife.87698 -
Life Science Alliance Jan 2024The intracellular positioning of the centrosome, a major microtubule-organizing center, is important for cellular functions. One of the features of centrosome...
The intracellular positioning of the centrosome, a major microtubule-organizing center, is important for cellular functions. One of the features of centrosome positioning is the spacing between centrosomes; however, the underlying mechanisms are not fully understood. To characterize the spacing activity in embryos, a genetic setup was developed to produce enucleated embryos. The centrosome was duplicated multiple times in the enucleated embryo, which enabled us to characterize the chromosome-independent spacing activity between sister and non-sister centrosome pairs. We found that the timely spacing depended on cytoplasmic dynein, and we propose a stoichiometric model of cortical and cytoplasmic pulling forces for the spacing between centrosomes. We also observed dynein-independent but non-muscle myosin II-dependent movement of centrosomes in the later cell cycle phase. The spacing mechanisms revealed in this study are expected to function between centrosomes in general, regardless of the presence of a chromosome/nucleus between them, including centrosome separation and spindle elongation.
Topics: Animals; Caenorhabditis elegans; Dyneins; Spindle Apparatus; Microtubules; Centrosome
PubMed: 37931957
DOI: 10.26508/lsa.202302427 -
The Journal of Cell Biology Dec 2023Neuronal autophagosomes form and engulf cargos at presynaptic sites in the axon and are then transported to the soma to recycle their cargo. Autophagic vacuoles (AVs)...
Neuronal autophagosomes form and engulf cargos at presynaptic sites in the axon and are then transported to the soma to recycle their cargo. Autophagic vacuoles (AVs) mature en route via fusion with lysosomes to become degradatively competent organelles; transport is driven by the microtubule motor protein cytoplasmic dynein, with motor activity regulated by a sequential series of adaptors. Using lysate-based single-molecule motility assays and live-cell imaging in primary neurons, we show that JNK-interacting proteins 3 (JIP3) and 4 (JIP4) are activating adaptors for dynein that are regulated on autophagosomes and lysosomes by the small GTPases ARF6 and RAB10. GTP-bound ARF6 promotes formation of the JIP3/4-dynein-dynactin complex. Either knockdown or overexpression of RAB10 stalls transport, suggesting that this GTPase is also required to coordinate the opposing activities of bound dynein and kinesin motors. These findings highlight the complex coordination of motor regulation during organelle transport in neurons.
Topics: Autophagosomes; Axonal Transport; Axons; Dyneins; Kinesins; rab GTP-Binding Proteins
PubMed: 37909920
DOI: 10.1083/jcb.202301084 -
Seizure Mar 2024The DYNC1H1 variants are associated with abnormal brain morphology and neuromuscular disorders that are accompanied by epilepsy. This study aimed to explore the...
OBJECTIVES
The DYNC1H1 variants are associated with abnormal brain morphology and neuromuscular disorders that are accompanied by epilepsy. This study aimed to explore the relationship between DYNC1H1 variants and epilepsy.
MATERIALS AND METHODS
Trios-based whole-exome sequencing was performed on patients with epilepsy. Previously reported epilepsy-related DYNC1H1 variants were systematically reviewed to analyse genotype-phenotype correlation.
RESULTS
The DYNC1H1 variants were identified in four unrelated cases of infant-onset epilepsy, including two de novo and two biallelic variants. Two patients harbouring de novo missense variants located in the stem and stalk domains presented with refractory epilepsies, whereas two patients harbouring biallelic variants located in the regions between functional domains had mild epilepsy with infrequent focal seizures and favourable outcomes. One patient presented with pachygyria and neurodevelopmental abnormalities, and the other three patients presented with normal development. These variants have no or low frequencies in the Genome Aggregation Database. All the missense variants were predicted to be damaging using silico tools. Previously reported epilepsy-related variants were monoallelic variants, mainly de novo missense variants, and all the patients presented with severe epileptic phenotypes or developmental delay and malformations of cortical development. Epilepsy-related variants were clustered in the dimerization and stalk domains, and generalized epilepsy-associated variants were distributed in the stem domain.
CONCLUSION
This study suggested that DYNC1H1 variants are potentially associated with infant-onset epilepsy without neurodevelopmental disorders, expanding the phenotypic spectrum of DYNC1H1. The genotype-phenotype correlation helps to understand the underlying mechanisms of phenotypic variation.
Topics: Infant; Humans; Mutation; Epilepsy; Neurodevelopmental Disorders; Epilepsy, Generalized; Mutation, Missense; Phenotype; Cytoplasmic Dyneins
PubMed: 37903666
DOI: 10.1016/j.seizure.2023.10.010 -
International Journal of Molecular... Oct 2023This review summarizes information about the specific features that are characteristic of the centrosome and its relationship with the cell function of highly... (Review)
Review
This review summarizes information about the specific features that are characteristic of the centrosome and its relationship with the cell function of highly specialized cells, such as endotheliocytes. It is based on data from other researchers and our own long-term experience. The participation of the centrosome in the functional activity of these cells, including its involvement in the performance of the main barrier function of the endothelium, is discussed. According to modern concepts, the centrosome is a multifunctional complex and an integral element of a living cell; the functions of which are not limited only to the ability to polymerize microtubules. The location of the centrosome near the center of the interphase cell, the concentration of various regulatory proteins in it, the organization of the centrosome radial system of microtubules through which intracellular transport is carried out by motor proteins and the involvement of the centrosome in the process of the perception of the external signals and their transmission make this cellular structure a universal regulatory and distribution center, controlling the entire dynamic morphology of an animal cell. Drawing from modern data on the tissue-specific features of the centrosome's structure, we discuss the direct involvement of the centrosome in the performance of functions by specialized cells.
Topics: Animals; Centrosome; Microtubules; Endothelial Cells; Dyneins; Endothelium
PubMed: 37895072
DOI: 10.3390/ijms242015392 -
Biomolecules Sep 2023Dynein motors facilitate the majority of minus-end-directed transport events on microtubules. The dynein adaptor Bicaudal D2 (BicD2) recruits the dynein machinery to...
Dynein motors facilitate the majority of minus-end-directed transport events on microtubules. The dynein adaptor Bicaudal D2 (BicD2) recruits the dynein machinery to several cellular cargo for transport, including Nup358, which facilitates a nuclear positioning pathway that is essential for the differentiation of distinct brain progenitor cells. Previously, we showed that Nup358 forms a "cargo recognition α-helix" upon binding to BicD2; however, the specifics of the BicD2-Nup358 interface are still not well understood. Here, we used AlphaFold2, complemented by two additional docking programs (HADDOCK and ClusPro) as well as mutagenesis, to show that the Nup358 cargo-recognition α-helix binds to BicD2 between residues 747 and 774 in an anti-parallel manner, forming a helical bundle. We identified two intermolecular salt bridges that are important to stabilize the interface. In addition, we uncovered a secondary interface mediated by an intrinsically disordered region of Nup358 that is directly N-terminal to the cargo-recognition α-helix and binds to BicD2 between residues 774 and 800. This is the same BicD2 domain that binds to the competing cargo adapter Rab6, which is important for the transport of Golgi-derived and secretory vesicles. Our results establish a structural basis for cargo recognition and selection by the dynein adapter BicD2, which facilitates transport pathways that are important for brain development.
Topics: Dyneins; Microtubule-Associated Proteins; Microtubules; Biological Transport; Models, Structural
PubMed: 37892127
DOI: 10.3390/biom13101445 -
Cells Oct 2023Axonemal dyneins are highly complex microtubule motors that power ciliary motility. These multi-subunit enzymes are assembled at dedicated sites within the cytoplasm. At...
Axonemal dyneins are highly complex microtubule motors that power ciliary motility. These multi-subunit enzymes are assembled at dedicated sites within the cytoplasm. At least nineteen cytosolic factors are specifically needed to generate dynein holoenzymes and/or for their trafficking to the growing cilium. Many proteins are subject to N-terminal processing and acetylation, which can generate degrons subject to the N-end rule, alter N-terminal electrostatics, generate new binding interfaces, and affect subunit stoichiometry through targeted degradation. Here, we have used mass spectrometry of cilia samples and electrophoretically purified dynein heavy chains from to define their N-terminal processing; we also detail the N-terminal acetylase complexes present in this organism. We identify four classes of dynein heavy chain based on their processing pathways by two distinct acetylases, one of which is dependent on methionine aminopeptidase activity. In addition, we find that one component of both the outer dynein arm intermediate/light chain subcomplex and the docking complex is processed to yield an unmodified Pro residue, which may provide a setpoint to direct the cytosolic stoichiometry of other dynein complex subunits that contain N-terminal degrons. Thus, we identify and describe an additional level of processing and complexity in the pathways leading to axonemal dynein formation in cytoplasm.
Topics: Axonemal Dyneins; Microtubules; Chlamydomonas; Cilia; Axoneme
PubMed: 37887336
DOI: 10.3390/cells12202492 -
Frontiers in Endocrinology 2023Primary cilia are microtubule-based organelles that are widespread on the cell surface and play a key role in tissue development and homeostasis by sensing and... (Review)
Review
Primary cilia are microtubule-based organelles that are widespread on the cell surface and play a key role in tissue development and homeostasis by sensing and transducing various signaling pathways. The process of intraflagellar transport (IFT), which is propelled by kinesin and dynein motors, plays a crucial role in the formation and functionality of cilia. Abnormalities in the cilia or ciliary transport system often cause a range of clinical conditions collectively known as ciliopathies, which include polydactyly, short ribs, scoliosis, thoracic stenosis and many abnormalities in the bones and cartilage. In this review, we summarize recent findings on the role of primary cilia and ciliary transport systems in bone development, we describe the role of cilia in bone formation, cartilage development and bone resorption, and we summarize advances in the study of primary cilia in fracture healing. In addition, the recent discovery of crosstalk between integrins and primary cilia provides new insights into how primary cilia affect bone.
Topics: Cilia; Flagella; Biological Transport; Kinesins; Dyneins
PubMed: 37886641
DOI: 10.3389/fendo.2023.1259650