Phosphorylation of RNA-binding protein controls cell cycle switch from mitotic to meiotic in fission yeast

Nature ◽  
1997 ◽  
Vol 386 (6621) ◽  
pp. 187-190 ◽  
Author(s):  
Yoshinori Watanabe ◽  
Satoko Shinozaki-Yabana ◽  
Yuji Chikashige ◽  
Yasushi Hiraoka ◽  
Masayuki Yamamoto
Author(s):  
Masashi Yukawa ◽  
Mitsuki Ohishi ◽  
Yusuke Yamada ◽  
Takashi Toda

Cells form a bipolar spindle during mitosis to ensure accurate chromosome segregation. Proper spindle architecture is established by a set of kinesin motors and microtubule-associated proteins. In most eukaryotes, kinesin-5 motors are essential for this process, and genetic or chemical inhibition of their activity leads to the emergence of monopolar spindles and cell death. However, these deficiencies can be rescued by simultaneous inactivation of kinesin-14 motors, as they counteract kinesin-5. We conducted detailed genetic analyses in fission yeast to understand the mechanisms driving spindle assembly in the absence of kinesin-5. Here we show that deletion of the nrp1 gene, which encodes a putative RNA-binding protein with unknown function, can rescue temperature sensitivity caused by cut7-22, a fission yeast kinesin-5 mutant. Interestingly, kinesin-14/Klp2 levels on the spindles in the cut7 mutants were significantly reduced by the nrp1 deletion, although the total levels of Klp2 and the stability of spindle microtubules remained unaffected. Moreover, RNA-binding motifs of Nrp1 are essential for its cytoplasmic localization and function. We have also found that a portion of Nrp1 is spatially and functionally sequestered by chaperone-based protein aggregates upon mild heat stress and limits cell division at high temperatures. We propose that Nrp1 might be involved in post-transcriptional regulation through its RNA-binding ability to promote the loading of Klp2 on the spindle microtubules.


2018 ◽  
Vol 69 (4) ◽  
pp. 622-635.e6 ◽  
Author(s):  
Cindy Meyer ◽  
Aitor Garzia ◽  
Michael Mazzola ◽  
Stefanie Gerstberger ◽  
Henrik Molina ◽  
...  

PLoS Genetics ◽  
2013 ◽  
Vol 9 (3) ◽  
pp. e1003367 ◽  
Author(s):  
Laetitia Davidovic ◽  
Nelly Durand ◽  
Olfa Khalfallah ◽  
Ricardo Tabet ◽  
Pascal Barbry ◽  
...  

2020 ◽  
Vol 219 (7) ◽  
Author(s):  
Therese M. Gerbich ◽  
Grace A. McLaughlin ◽  
Katelyn Cassidy ◽  
Scott Gerber ◽  
David Adalsteinsson ◽  
...  

Biomolecular condensation is a way of organizing cytosol in which proteins and nucleic acids coassemble into compartments. In the multinucleate filamentous fungus Ashbya gossypii, the RNA-binding protein Whi3 regulates the cell cycle and cell polarity through forming macromolecular structures that behave like condensates. Whi3 has distinct spatial localizations and mRNA targets, making it a powerful model for how, when, and where specific identities are established for condensates. We identified residues on Whi3 that are differentially phosphorylated under specific conditions and generated mutants that ablate this regulation. This yielded separation of function alleles that were functional for either cell polarity or nuclear cycling but not both. This study shows that phosphorylation of individual residues on molecules in biomolecular condensates can provide specificity that gives rise to distinct functional identities in the same cell.


Author(s):  
Daniela D’Angelo ◽  
Claudio Arra ◽  
Alfredo Fusco

Long noncoding RNAs have been recently demonstrated to have an important role in fundamental biological processes, and their deregulated expression has been found in several human neoplasias. Our group has recently reported a drastic overexpression of the long noncoding RNA (lncRNA) RPSAP52 (ribosomal protein SA pseudogene 52) in pituitary adenomas. We have shown that this lncRNA increased cell proliferation by upregulating the expression of the chromatinic proteins HMGA1 and HMGA2, functioning as a competing endogenous RNA (ceRNA) through competitively binding to microRNA-15a (miR-15a), miR-15b, and miR-16. The aim of this work was to identify further mechanisms by which RPSAP52 overexpression could contribute to the development of pituitary adenomas. We investigated the involvement of RPSAP52 in the modulation of the expression of cell cycle-related genes, such as p21Waf1/CIP, whose deregulation plays a critical role in pituitary cell transformation. We report that RPSAP52, interacting with the RNA binding protein HuR (human antigen R), favors the delocalization of miR-15a, miR-15b, and miR-16 on the cyclin-dependent kinase inhibitor p21Waf1/CIP1 that, accordingly, results in downregulation in pituitary adenomas. A RNA immunoprecipitation sequencing (RIPseq) analysis performed on cells overexpressing RPSAP52 identified 40 messenger RNAs (mRNAs) enriched in Argonaute 2 (AGO2) immunoprecipitated samples. Among them, we focused on GAS8 (growth arrest-specific protein 8) gene. Consistently, GAS8 expression was downregulated in all the analyzed pituitary adenomas with respect to normal pituitary and in RPSAP52-overepressing cells, supporting the role of RPSAP52 in addressing genes involved in growth inhibition and cell cycle arrest to miRNA-induced degradation. This study unveils another RPSAP52-mediated molecular mechanism in pituitary tumorigenesis.


2019 ◽  
Vol 80 (2) ◽  
pp. 219-233 ◽  
Author(s):  
Xin-Yi Loh ◽  
Qiao-Yang Sun ◽  
Ling-Wen Ding ◽  
Anand Mayakonda ◽  
Nachiyappan Venkatachalam ◽  
...  

2017 ◽  
Vol 11 (2) ◽  
pp. 123-126 ◽  
Author(s):  
Ayaho Kobayashi ◽  
Teppei Kanaba ◽  
Ryosuke Satoh ◽  
Yutaka Ito ◽  
Reiko Sugiura ◽  
...  

Cell Cycle ◽  
2011 ◽  
Vol 10 (16) ◽  
pp. 2703-2713 ◽  
Author(s):  
Guodong Yang ◽  
Xiaozhao Lu ◽  
Li Wang ◽  
Yongqian Bian ◽  
Haiyan Fu ◽  
...  

2009 ◽  
Vol 20 (9) ◽  
pp. 2473-2485 ◽  
Author(s):  
Ryosuke Satoh ◽  
Takahiro Morita ◽  
Hirofumi Takada ◽  
Ayako Kita ◽  
Shunji Ishiwata ◽  
...  

Myosin II is an essential component of the actomyosin contractile ring and plays a crucial role in cytokinesis by generating the forces necessary for contraction of the actomyosin ring. Cdc4 is an essential myosin II light chain in fission yeast and is required for cytokinesis. In various eukaryotes, the phosphorylation of myosin is well documented as a primary means of activating myosin II, but little is known about the regulatory mechanisms of Cdc4. Here, we isolated Nrd1, an RNA-binding protein with RNA-recognition motifs, as a multicopy suppressor of cdc4 mutants. Notably, we demonstrated that Nrd1 binds and stabilizes Cdc4 mRNA, thereby suppressing the cytokinesis defects of the cdc4 mutants. Importantly, Pmk1 mitogen-activated protein kinase (MAPK) directly phosphorylates Nrd1, thereby negatively regulating the binding activity of Nrd1 to Cdc4 mRNA. Consistently, the inactivation of Pmk1 MAPK signaling, as well as Nrd1 overexpression, stabilized the Cdc4 mRNA level, thereby suppressing the cytokinesis defects associated with the cdc4 mutants. In addition, we demonstrated the cell cycle–dependent regulation of Pmk1/Nrd1 signaling. Together, our results indicate that Nrd1 plays a role in the regulation of Cdc4 mRNA stability; moreover, our study is the first to demonstrate the posttranscriptional regulation of myosin expression by MAPK signaling.


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