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Volume 35 (2010)
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Volume 35, Issue 1
Displaying 1-8 of 8 articles from this issue
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Yujian Lu, Zhenyu Wang, Liang Ge, Ni Chen, Heng Liu2010 Volume 35 Issue 1 Pages 1
Published: 2010
Released on J-STAGE: January 20, 2010
JOURNAL FREE ACCESSThis article has been retracted at the request of the Editor-in-Chief of the Cell Structure and Function. This review article contains a substantial amount of text that had previously appeared in other published articles, including the Elsevier journals Current Biology (Howell et al., Curr. Biol. 2004 Jun 8; 14(11): 953-964), Trends in Cell Biology (Karess, Trends Cell Biol. 2005 Jul; 15(7): 386-392) and Current Opinion in Cell Biology (Yu, Curr. Opin. Cell Biol. 2002 Dec; 14(6): 706-714). In accordance with policies and procedures governing academic publication we concluded that the above-mentioned article published in Cell Struct. Funct. be retracted. We apologize to readers of the journals that this was not detected during the submission and review process.View full abstractDownload PDF (43K) -
Tomoko Ichise, Satoshi Adachi, Minako Ohishi, Masahito Ikawa, Masaru O ...2010 Volume 35 Issue 1 Pages 3-13
Published: 2010
Released on J-STAGE: February 27, 2010
JOURNAL FREE ACCESS FULL-TEXT HTMLTumor progression is a complex process that involves the interaction of cancer cells with the cancer-surrounding stromal cells. The cancer stroma influences the cancer cell growth and metastatic potential. The EGF family growth factor HB-EGF is synthesized in cancer cells and plays pivotal roles in oncogenic transformation and tumor progression, but the contribution of HB-EGF expressed in tumor stromal cells to tumor growth remains unclear. In the present study, we found that HB-EGF was expressed in host-derived cancer stromal cells in xenograft and allograft mouse tumor models. CRM197 is a specific inhibitor of human HB-EGF that has no effect on mouse HB-EGF. To elucidate whether host-derived stromal HB-EGF contributes to tumor growth, we generated knock-in mice expressing a CRM197-inhibitable humanized mutant form of HB-EGF. Administration of CRM197 to humanized knock-in mice that were bearing tumors derived from human or mouse cancer cells revealed that inhibition of host-derived stromal HB-EGF by CRM197 significantly reduced tumor growth. These results suggest that HB-EGF in the cancer-associated stroma plays a significant role for tumor growth, and that the HB-EGF derived from the stroma, as well as that expressed by cancer cells, is a potential target for cancer therapy. The present results also suggest that the humanized HB-EGF knock-in mice could be utilized for pathophysiological studies of HB-EGF as well as the development of therapeutic strategies targeting HB-EGF.
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Koji Ikegami, Mitsutoshi Setou2010 Volume 35 Issue 1 Pages 15-22
Published: 2010
Released on J-STAGE: April 13, 2010
Advance online publication: February 27, 2010JOURNAL FREE ACCESS FULL-TEXT HTMLMicrotubules (MTs) play specialized roles in a wide variety of cellular events, e.g. molecular transport, cell motility, and cell division. Specialized MT architectures, such as bundles, axonemes, and centrioles, underlie the function. The specialized function and highly organized structure depend on interactions with MT-binding proteins. MT-associated proteins (e.g. MAP1, MAP2, and tau), molecular motors (kinesin and dynein), plus-end tracking proteins (e.g. CLIP-170), and MT-severing proteins (e.g. katanin) interact with MTs. How can the MT-binding proteins know temporospatial information to associate with MTs and to properly play their roles? Post-translational modifications (PTMs) including detyrosination, polyglutamylation, and polyglycylation can provide molecular landmarks for the proteins. Recent efforts to identify modification-regulating enzymes (TTL, carboxypeptidase, polyglutamylase, polyglycylase) and to generate genetically manipulated animals enable us to understand the roles of the modifications. In this review, we present recent advances in understanding regulation of MT function, structure, and stability by PTMs.
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Takashi Ikeda2010 Volume 35 Issue 1 Pages 23-30
Published: 2010
Released on J-STAGE: April 13, 2010
Advance online publication: March 10, 2010JOURNAL FREE ACCESS FULL-TEXT HTMLNucleoside diphosphate (NDP) kinase is an enzyme that synthesizes the nucleoside triphosphates. In mammals, nine sequences (NDK1-NDK9) have been found with domain(s) homologous to the catalytic domain of NDP kinase, and some of them have been shown to associate with sperm flagella. The present study examines the localization of NDK7, for which little information has been available. Database analysis showed that the NDK7 gene is present in organisms with cilia and flagella. Western blotting analyses of various mouse tissues consistently indicated that NDK7 is preferentially expressed in tissues with motile cilia as well as in sperm. Immunofluorescence microscopy revealed that this protein is localized along the entire length of the TritonX-100-insoluble fraction of sperm flagella, possibly in the axonemes. Unexpectedly, however, NDK7 in tracheal epithelia was found in the cell body but not in cilia. Finally, in vitro co-sedimentation assays using recombinant proteins showed that both mouse and Chlamydomonas NDK7 directly bind to microtubules.
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Andrea Harničarová Horáková, Eva Bá ...2010 Volume 35 Issue 1 Pages 31-44
Published: 2010
Released on J-STAGE: May 20, 2010
Advance online publication: April 15, 2010JOURNAL FREE ACCESS FULL-TEXT HTMLHere, we would like to point out important milestones in the study of nuclear radial positioning and gene expression during differentiation processes. In addition, changes in the histone signature that significantly precede various differentiation pathways are reviewed. We address the regulatory functions of chromatin structure and histone epigenetic marks that give rise to gene expression patterns that are specific to distinct differentiation pathways. The functional relevance of nuclear architecture and epigenetic traits is preferentially discussed in the context of in vitro induced enterocytic differentiation and pluripotent or differentiated embryonic stem cells. We especially focus on the recapitulation of nuclear events that have been characterized for some genes and proto-oncogenes that are important for development and differentiation.
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Satohiro Okuda, Tetsuya Higashiyama2010 Volume 35 Issue 1 Pages 45-52
Published: 2010
Released on J-STAGE: June 17, 2010
JOURNAL FREE ACCESS FULL-TEXT HTMLSexual reproduction in flowering plants requires pollen-tube guidance, which is thought to be mediated by chemoattractants derived from target ovules. To date, however, no convincing evidence has been reported of a particular molecule being the true attractant. Emerging data indicate that two synergid cells, which are on either side of the egg cell, emit a diffusible, species-specific signal to attract the pollen tube at the last step of pollen-tube guidance. Recently, it was demonstrated that LUREs (LURE1 and LURE2), cysteine-rich polypeptides secreted from the synergid cell, are the key molecules in pollen-tube guidance. In this review, we summarize the mechanism of pollen-tube guidance, with special focus on gametophytic guidance and the attractants.
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Takashi Nakamura, Hidetoshi Toita, Akimasa Yoshimoto, Daigo Nishimura, ...2010 Volume 35 Issue 1 Pages 53-61
Published: 2010
Released on J-STAGE: June 17, 2010
Advance online publication: April 24, 2010JOURNAL FREE ACCESS FULL-TEXT HTMLEpidermal growth factor (EGF) family members play important roles in the skeletal system. In this study, we examined the role of EGF receptor (EGFR) signaling in osteoblastogenesis in vitro. The expression of HB-EGF and epiregulin (EPR) was transiently induced within 24 h after osteogenic stimulation, but when preosteoblastic MC3T3-E1 cells were incubated with HB-EGF or EPR, osteoblast differentiation was inhibited. These effects were Ras-dependent, and ERK modulated Runx2 activity through the localization of Smad1 and the induction of Twist2. PI3-kinase was also required for the induction of Twist2. However, the inhibition of individual signaling pathways was not sufficient to overcome HB-EGF-mediated inhibition of osteoblast differentiation. Additionally, HB-EGF treatment promoted the proliferation of preosteoblasts, and this was associated with the downregulation of p27 at the protein level. These results suggest that HB-EGF-EGFR signaling inhibits the differentiation of osteoblasts by suppression of Runx2 transcriptional activity and enhances proliferation of preosteoblasts by downregulation of expression of p27.
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Yosuke Nagata, Yusuke Honda, Ryoichi Matsuda2010 Volume 35 Issue 1 Pages 63-71
Published: 2010
Released on J-STAGE: June 17, 2010
Advance online publication: May 01, 2010JOURNAL FREE ACCESS FULL-TEXT HTMLSatellite cells are muscle-resident stem cells, which are located beneath the basement membrane of myofibers. Because the number of satellite cells is normally constant, there must be a tight regulation of satellite cell activation and self-renewal. However, the molecular mechanisms involved in satellite cell maintenance are largely unknown, and thus have become the subject of extensive study these days. Although RNA interference with a small interfering RNA has been widely used to investigate the role of specific gene products, inefficient knockdown of Grb2 expression occurred in quiescent reserve cells, a model for quiescent satellite cells, by ordinary transfection protocol. In this study we report that pretreatment with trypsin greatly enhanced siRNA delivery into quiescent reserve cells, resulting in efficient silencing of Grb2 expression. By applying a combination of Grb2-silencing and protein kinase C inhibitors, we demonstrated that extracellular signal-regulated kinase (ERK) phosphorylation induced with fibroblast growth factor 2 (FGF2) was dependent on both Grb2 and protein kinase C (PKC) with different kinetics. We concluded that the PKC-mediated pathway contributes to rapid initiation and termination of ERK phosphorylation, while the Grb2-mediated pathway contributes to delayed and sustained ERK phosphorylation.
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