Dataset Information

The J-domain cochaperone Rsp1 interacts with Mto1 to organize noncentrosomal microtubule assembly.

ABSTRACT: Microtubule biogenesis initiates at various intracellular sites, including the centrosome, the Golgi apparatus, the nuclear envelope, and preexisting microtubules. Similarly, in the fission yeast Schizosaccharomyces pombe, interphase microtubules are nucleated at the spindle pole body (SPB), the nuclear envelope, and preexisting microtubules, depending on Mto1 activity. Despite the essential role of Mto1 in promoting microtubule nucleation, how distribution of Mto1 in different sites is regulated has remained elusive. Here, we show that the J-domain cochaperone Rsp1 interacts with Mto1 and specifies the localization of Mto1 to non-SPB nucleation sites. The absence of Rsp1 abolishes the localization of Mto1 to non-SPB nucleation sites, with concomitant enrichment of Mto1 to the SPB and the nuclear envelope. In contrast, Rsp1 overexpression impairs the localization of Mto1 to all microtubule organization sites. These findings delineate a previously uncharacterized mechanism in which Rsp1-Mto1 interaction orchestrates non-SPB microtubule formation.

SUBMITTER: Shen J

PROVIDER: S-EPMC6589567 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The J-domain cochaperone Rsp1 interacts with Mto1 to organize noncentrosomal microtubule assembly.

Shen Juan J Li Tianpeng T Niu Xiaojia X Liu Wenyue W Zheng Shengnan S Wang Jing J Wang Fengsong F Cao Xinwang X Yao Xuebiao X Zheng Fan F Fu Chuanhai C

Molecular biology of the cell 20181114 2

Microtubule biogenesis initiates at various intracellular sites, including the centrosome, the Golgi apparatus, the nuclear envelope, and preexisting microtubules. Similarly, in the fission yeast Schizosaccharomyces pombe, interphase microtubules are nucleated at the spindle pole body (SPB), the nuclear envelope, and preexisting microtubules, depending on Mto1 activity. Despite the essential role of Mto1 in promoting microtubule nucleation, how distribution of Mto1 in different sites is regulate ...[more]

PMID: 30427751

Similar Datasets

Project description:Rationale: Emerging evidence suggests that noncentrosomal microtubules play an essential role in intracellular transport, cell polarity and cell motility. Whether these noncentrosomal microtubules exist or function in cancer cells remains unclear. Methods: The expression and prognostic values of CAMSAP2 and its functional targets were analyzed by immunohistochemistry in two independent HCC cohorts. Immunofluorescence and co-immunoprecipitation were used for detection of CAMSAP2-decorated noncentrosomal microtubule. Chromatin immunoprecipitation and luciferase report assays were used to determine the c-Jun binding sites in HDAC6 promoter region. In vitro migration and invasion assays and in vivo orthotopic metastatic models were utilized to investigate invasion and metastasis. Results: We reported a microtubule minus‑end‑targeting protein, CAMSAP2, is significantly upregulated in hepatocellular carcinoma (HCC) and correlated with poor prognosis. CAMSAP2 was specifically deposited on microtubule minus ends to serve as a "seed" for noncentrosomal microtubule outgrowth in HCC cells. Upon depletion of CAMSAP2, the noncentrosomal microtubule array was transformed into a completely radial centrosomal pattern, thereby impairing HCC cell migration and invasion. We further demonstrated that CAMSAP2 cooperates with EB1 to regulate microtubule dynamics and invasive cell migration via Trio/Rac1 signaling. Strikingly, both immunofluorescence staining and western blotting showed that CAMSAP2 depletion strongly reduced the abundance of acetylated microtubules in HCC cells. Our results revealed that HDAC6, a promising target for cancer therapy, was inversely downregulated in HCC and uniquely endowed with tumor-suppressive activity by regulation CAMSAP2-mediated microtubule acetylation. Mechanistically, CAMSAP2 activates c-Jun to induce transrepression of HDAC6 through Trio-dependent Rac1/JNK pathway. Furthermore, NSC23766, a Rac1-specific inhibitor significantly inhibited CAMSAP2-mediated HCC invasion and metastasis. Conclusions: CAMSAP2 is functionally, mechanistically, and clinically oncogenic in HCC. Targeting CAMSAP2-mediated noncentrosomal microtubule acetylation may provide new therapeutic strategies for HCC metastasis.

Project description:Previous data suggested that anastral spindles, morphologically similar to those found in oocytes, can assemble in a centrosome-independent manner in cells that contain centrosomes. It is assumed that the microtubules that build these acentrosomal spindles originate over the chromatin. However, the actual processes of centrosome-independent microtubule nucleation, polymerisation, and sorting have not been documented in centrosome-containing cells. We have identified two experimental conditions in which centrosomes are kept close to the plasma membrane, away from the nuclear region, throughout meiosis I in Drosophila spermatocytes. Time-lapse confocal microscopy of these cells labelled with fluorescent chimeras reveals centrosome-independent microtubule nucleation, growth, and sorting into a bipolar spindle array over the nuclear region, away from the asters. The onset of noncentrosomal microtubule nucleation is significantly delayed with respect to nuclear envelope breakdown and coincides with the end of chromosome condensation. It takes place in foci that are close to the membranes that ensheath the nuclear region, not over the condensed chromosomes. Metaphase plates are formed in these spindles, and, in a fraction of them, some degree of polewards chromosome segregation takes place. In these cells that contain both membrane-bound asters and an anastral spindle, the orientation of the cytokinesis furrow correlates with the position of the asters and is independent of the orientation of the spindle. We conclude that the fenestrated nuclear envelope may significantly contribute to the normal process of spindle assembly in Drosophila spermatocytes. We also conclude that the anastral spindles that we have observed are not likely to provide a robust back-up able to ensure successful cell division. We propose that these anastral microtubule arrays could be a constitutive component of wild-type spindles, normally masked by the abundance of centrosome-derived microtubules and revealed when asters are kept away. These observations are consistent with a model in which centrosomal and noncentrosomal microtubules contribute to the assembly and are required for the robustness of the cell division spindle in cells that contain centrosomes.

Dataset Information

The J-domain cochaperone Rsp1 interacts with Mto1 to organize noncentrosomal microtubule assembly.

Publications

The J-domain cochaperone Rsp1 interacts with Mto1 to organize noncentrosomal microtubule assembly.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets