scholarly journals Hippo Pathway in Organ Size Control, Tissue Homeostasis, and Cancer

Cell ◽  
2015 ◽  
Vol 163 (4) ◽  
pp. 811-828 ◽  
Author(s):  
Fa-Xing Yu ◽  
Bin Zhao ◽  
Kun-Liang Guan
eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Helen Rankin Willsey ◽  
Xiaoyan Zheng ◽  
José Carlos Pastor-Pareja ◽  
A Jeremy Willsey ◽  
Philip A Beachy ◽  
...  

A fundamental question of biology is what determines organ size. Despite demonstrations that factors within organs determine their sizes, intrinsic size control mechanisms remain elusive. Here we show that Drosophila wing size is regulated by JNK signaling during development. JNK is active in a stripe along the center of developing wings, and modulating JNK signaling within this stripe changes organ size. This JNK stripe influences proliferation in a non-canonical, Jun-independent manner by inhibiting the Hippo pathway. Localized JNK activity is established by Hedgehog signaling, where Ci elevates dTRAF1 expression. As the dTRAF1 homolog, TRAF4, is amplified in numerous cancers, these findings provide a new mechanism for how the Hedgehog pathway could contribute to tumorigenesis, and, more importantly, provides a new strategy for cancer therapies. Finally, modulation of JNK signaling centers in developing antennae and legs changes their sizes, suggesting a more generalizable role for JNK signaling in developmental organ size control.


Development ◽  
2010 ◽  
Vol 137 (5) ◽  
pp. 735-743 ◽  
Author(s):  
C. C. Milton ◽  
X. Zhang ◽  
N. O. Albanese ◽  
K. F. Harvey

Open Biology ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 180029 ◽  
Author(s):  
Zi Liang ◽  
Yahong Lu ◽  
Ying Qian ◽  
Liyuan Zhu ◽  
Sulan Kuang ◽  
...  

Hippo signalling represents a cell proliferation and organ-size control pathway. Yorki (Yki), a component of the Hippo pathway, induces the transcription of a number of targets that promote cell proliferation and survival. The functions of Yki have been characterized in Drosophila and mammals, while there are few reports on silkworm, Bombyx mori . In the present study, we found that BmYki3 facilitates cell migration and cell division, and enlarges the cultured cell and wing disc size. Co-immunoprecipitation results indicated that BmYki3 may interact with thymosin, E3 ubiquitin-protein ligase, protein kinase ASK1, dedicator of cytokinesis protein 1, calcium-independent phospholipase A2 and beta-spectrin. RNA-seq results indicated that 4444 genes were upregulated and 10 291 genes were downregulated after BmYki3 was overexpressed in the cultured cells. GO annotation indicated that the up/downregulated genes were enriched in 268/382 GO terms ( p < 0.01); KEGG analysis showed that the up/downregulated genes were enriched in 49/101 pathways. These findings provided novel information to understand the functions of BmYki3 in a cell proliferation and organ-size control pathway.


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Sung Jun Bae ◽  
Lisheng Ni ◽  
Xuelian Luo

The MST-LATS kinase cascade is central to the Hippo pathway that controls tissue homeostasis, development, and organ size. The PP2A complex STRIPAKSLMAP blocks MST1/2 activation. The GCKIII family kinases associate with STRIPAK, but the functions of these phosphatase-associated kinases remain elusive. We previously showed that the scaffolding protein SAV1 promotes Hippo signaling by counteracting STRIPAK (Bae et al., 2017). Here, we show that the GCKIII kinase STK25 promotes STRIPAK-mediated inhibition of MST2 in human cells. Depletion of STK25 enhances MST2 activation without affecting the integrity of STRIPAKSLMAP. STK25 directly phosphorylates SAV1 and diminishes the ability of SAV1 to inhibit STRIPAK. Thus, STK25 as the kinase component of STRIPAK can inhibit the function of the STRIPAK inhibitor SAV1. This mutual antagonism between STRIPAK and SAV1 controls the initiation of Hippo signaling.


2019 ◽  
Author(s):  
Joseph H.A. Vissers ◽  
Lucas G. Dent ◽  
Colin House ◽  
Shu Kondo ◽  
Kieran F. Harvey

ABSTRACTThe Hippo pathway is an evolutionary conserved signalling network that regulates organ size, cell fate control and tumorigenesis. In the context of organ size control, the pathway incorporates a large variety of cellular cues such as cell polarity and adhesion into an integrated transcriptional response. The central Hippo signalling effector is the transcriptional co-activator Yorkie, which controls gene expression in partnership with different transcription factors, most notably Scalloped. When it is not activated by Yorkie, Scalloped can act as a repressor of transcription, at least in part due to its interaction with the corepressor protein Tgi. The mechanism by which Tgi represses transcription is incompletely understood and therefore we sought to identify proteins that potentially operate together with it. Using an affinity purification and mass-spectrometry approach we identified Pits and CtBP as Tgi-interacting proteins, both of which have been linked to transcriptional repression. Both Pits and CtBP were required for Tgi to suppress the growth of the D. melanogaster eye and CtBP loss suppressed the undergrowth of yorkie mutant eye tissue. Furthermore, as reported previously for Tgi, overexpression of Pits suppressed transcription of Hippo pathway target genes. These findings suggest that Tgi might operate together with Pits and CtBP to repress transcription of genes that normally promote tissue growth. The human orthologues of Tgi, CtBP and Pits (VGLL4, CTBP2 and IRF2BP2) physically and functionally interact to control transcription, implying that the mechanism by which these proteins control transcriptional repression is conserved throughout evolution.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Lu Jie ◽  
Wang Fan ◽  
Dai Weiqi ◽  
Zhou Yingqun ◽  
Xu Ling ◽  
...  

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and the third leading cause of cancer mortality. Despite continuing development of new therapies, prognosis for patients with HCC remains extremely poor. In recent years, control of organ size becomes a hot topic in HCC development. The Hippo signaling pathway has been delineated and shown to be critical in controlling organ size in both Drosophila and mammals. The Hippo kinase cascade, a singling pathway that antagonizes the transcriptional coactivator Yes-associated protein (YAP), plays an important role in animal organ size control by regulating cell proliferation and apoptosis rates. During HCC development, this pathway is likely inactivated in tumor initiated cells that escape suppressive constrain exerted by the surrounding normal tissue, thus allowing clonal expansion and tumor development. We have reviewed evolutionary changes in YAP as well as other components of the Hippo pathway and described the relationships between YAP genes and HCC. We also discuss regulation of transcription factors that are up- and downstream of YAP in liver cancer development.


2020 ◽  
Vol 64 (4-5-6) ◽  
pp. 299-318
Author(s):  
Carmen M.A. Coelho

The regulation of growth and the determination of organ-size in animals is an area of research that has received much attention during the past two and a half decades. Classic regeneration and cell-competition studies performed during the last century suggested that for size to be determined, organ-size is sensed and this sense of size feeds back into the growth control mechanism such that growth stops at the “correct” size. Recent work using Drosophila imaginal discs as a system has provided a particularly detailed cellular and molecular understanding of growth. Yet, a clear mechanistic basis for size-sensing has not emerged. I re-examine these studies from a different perspective and ask whether there is scope for alternate modes of size control in which size does not need to be sensed.


Sign in / Sign up

Export Citation Format

Share Document