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Yang, B.-J.

Publications and source records attributed to Yang, B.-J..

4 recordsLinked to original sources

The DDIT4L-TOM40-ATP5A pathway suppresses glioblastoma oncogenesis

The characteristics of glioblastoma (GBM), including resistance to cell death and aberrant energy metabolism, are associated with the function of mitochondria. To date, the inherent suppressors that couple mitochondrial function with cell death remain unclear. DNA damage-inducible transcript 4-like (DDIT4L) expression in human gliomas and its association with patient survival was determined by public databases, western-blot and immunostaining. The role of DDIT4L in regulating tumor growth was analyzed using lentivirus and PDX model. The mechanism of DDIT4L on GBM mitochondrial function was determined by different assays. Here, we show that DDIT4L is an endogenous inhibitor of GBM via suppressing mitochondrial function. DDIT4L was expressed at high levels in GBM and transported into mitochondria via single import channel TOM40 other than the import receptors TOM22, TOM20 or TOM70. Then, DDIT4L interacted with the subunit of ATP synthase, inhibited mitochondrial function and induced tumor cell apoptosis. Furthermore, the synthetic peptide DDIT4LV125-P132 suppressed GBM oncogenesis. Based on these results, DDIT4L suppresses GBM oncogenesis through both TOM40- and ATP5A-dependent mechanisms to curb mitochondrial dynamics and induce cell apoptosis, and the DDIT4LV125-P132 peptide is a potential therapy for GBM.

cancer biology↗

MYB12 spatiotemporally represses TMO5/LHW-mediated transcription in the Arabidopsis root meristem

Transcriptional networks are crucial to integrate various internal and external signals into optimal responses during plant growth and development. Primary root vasculature patterning and proliferation are controlled by a network centred around the basic Helix-Loop-Helix transcription factor complex formed by TARGET OF MONOPTEROS 5 (TMO5) and LONESOME HIGHWAY (LHW), which control cell proliferation and orientation by modulating cytokinin response and other downstream factors. Despite recent progress, many aspects of the TMO5/LHW pathway are not fully understood. In particular, the upstream regulators of TMO5/LHW activity remain unknown. Here, using a forward genetic approach to identify new factors of the TMO5/LHW pathway, we discovered a novel function of the MYB-type transcription factor MYB12. MYB12 physically interacts with TMO5 and dampens the TMO5/LHW-mediated induction of direct target gene expression as well as the periclinal/radial cell divisions. The expression of MYB12 is activated by the cytokinin response, downstream of TMO5/LHW, resulting in a novel MYB12-mediated negative feedback loop that restricts TMO5/LHW activity to ensure optimal cell proliferation rates during root vascular development.

plant biology↗

OsIQD14 regulates rice grain shape through modulating the microtubule cytoskeleton

Cortical microtubule (MT) arrays play a critical role in plant cell shape determination by defining the direction of cell expansion1-3. The control of plant organ shape and architecture is a major target of cereal crop improvement. Given the pleiotropic effects of MT modification, however, it is challenging to exploiting MT array organization for crop improvement. Moreover, as plants continuously adapt cell growth and expansion to ever-changing environmental conditions, multiple environmental (e.g. light4) and developmental (e.g. hormones5,6) inputs need to be translated into changes of the MT cytoskeleton. Here, we identify and functionally characterize an auxin-inducible and MT-localized protein OsIQ67-DOMAIN14 (OsIQD14), which is highly expressed in rice seed hull cells. While deficiency of OsIQD14 results in short and wide seeds and increases overall yield, overexpression leads to narrow and long seeds, caused by changes in the direction of MT arrangement. We further show that OsIQD14-mediated MT reordering is regulated through interacting with SPIRAL2, a MT-binding protein involved in KATANIN1-mediated MT rearrangement7,8, and with calmodulin proteins. As such, OsIQD14 acts as an integrator of auxin and calcium inputs into MT rearrangements, and allows effective local cell shape manipulation to improve a key rice yield trait.

plant biology↗

IQD proteins integrate auxin and calcium signaling to regulate microtubule dynamics during Arabidopsis development

Geometry and growth and division direction of individual cells are major contributors to plant organ shape and these processes are dependent on dynamics of microtubules (MT). Different MT structures, like the cortical microtubules, preprophase band and mitotic spindle, are characterized by diverse architectural dynamics (Hashimoto, 2015). While several MT binding proteins have been identified that have various effects on MT stability and architecture, they do not discriminate between the different MT structures. It is therefore likely that specific MT binding proteins exist that differentiate between MT structures in order to allow for the differences in architectural dynamics. Although evidence for the effect of specific cues, such as light and auxin, on MT dynamics has been shown in recent years (Lindeboom et al., 2013; Chen et al., 2014), it remains unknown how such cues are integrated and lead to specific effects. Here we provide evidence for how auxin and calcium signaling can be integrated to modulate MT dynamics, by means of IQD proteins. We show that the Arabidopsis IQD15-18 subclade of this family is regulated by auxin signaling, can bind calmodulins in a calcium-dependent manner and are evolutionarily conserved. Furthermore, AtIQD15-18 directly bind SPIRAL2 protein in vitro and in vivo and modulate its function, likely in a calmodulin-dependent way, thereby providing a missing link between two important regulatory pathways of MT dynamics.\n\nOne sentence summaryIQD proteins integrate auxin and calcium signaling, two major signaling pathways, to control the cytoskeleton dynamics and cell shape of Arabidopsis.

plant biology↗