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Biology subjects

Huang, Y.-Z.

Publications and source records attributed to Huang, Y.-Z..

2 recordsLinked to original sources

Autophagy-Dependent Regulation of YAP1 by STK38 Governs Recruitment of Differentiated Cells as Progenitor Cells During Regeneration

Paligenosis is a conserved cellular plasticity program that allows mature cells to reenter the cell cycle in response to tissue injury. Paligenosis progresses via three stages: autodegradation (with dramatic increase in autophagy and lysosomes), induction of metaplastic or fetal-like genes, and cell cycle entry. Hippo signaling, particularly the downstream effector YAP1, regulates cellular plasticity, but its role in paligenosis has not been studied. Here we first examine paligenosis in digestive-enzyme-secreting chief cells in mouse stomach. We identify Serine/Threonine Kinase 38 (STK38) as a non-canonical YAP1 kinase that phosphorylated and deactivated YAP1 in uninjured chief cells. During paligenosis, STK38 was degraded by autophagy in stage 1, dephosphorylating and activating YAP1. YAP1 activation was necessary and sufficient for the paligenosis that converts chief cells into metaplastic, proliferating progenitors. Additionally, we show STK38, like canonical Hippo kinases, interact with NF2. We also observed the same pattern of YAP1 induction via autophagic destruction of STK38 in other tissues and cell types, suggesting a universal logic model for how the massive autophagy activated in differentiated cells during tissue damage can consequently activate Hippo effectors to induce plasticity for tissue regeneration.

developmental biology↗

Inhibition of Ribosome Biogenesis in vivo Causes p53-Dependent Death and p53-Independent Dysfunction

Ribosomes are critical for cell function; their synthesis (known as ribosome biogenesis; "RiBi") is complex and energy-intensive. Surprisingly little is known about RiBi in differentiated cells in vivo in adult tissue. Here, we generated mice with conditional deletion of Nat10, an essential gene for RiBi and translation, to investigate effects of RiBi blockade in vivo. We focused on RiBi in a long-lived, ribosome-rich cell population, pancreatic acinar cells, during homeostasis and tumorigenesis. We observed a surprising latency of several weeks between Nat10 deletion and onset of structural and functional abnormalities and p53-dependent acinar cell death, which was associated with translocation of ribosomal proteins RPL5 and RPL11 into acinar cell nucleoplasm. Indeed, deletion of Trp53 could rescue acinar cells from apoptotic cell death; however, Nat10{Delta}/{Delta}; Trp53{Delta}/{Delta} acinar cells remained morphologically and functionally abnormal. Moreover, the deletion of Trp53 did not rescue the lethality of inducible, globally deleted Nat10 in adult mice nor did it rescue embryonic lethality of global Nat10 deletion, emphasizing p53-independent consequences of RiBi inhibition. Deletion of Nat10 in acinar cells blocked Kras-oncogene-driven pancreatic intraepithelial neoplasia and subsequent pancreatic ductal adenocarcinoma, regardless of Trp53 mutation status. Together, our results provide initial insights into how cells respond to defects in RiBi and translation in vivo.

cell biology↗