Human immediate early response 2 (IER2) has been reported to function as a potential transcriptional factor or transcriptional co‑activator and seems to play a pivotal role in tumor cell motility and metastasis, however, its role and underlying mechanisms in hepatocellular carcinoma (HCC) remain unknown. Herein, we demonstrated that overexpression of IER2 in HCC cells increased cell adhesion to fibronectin, migration and invasion, whereas knockdown of IER2 displayed the opposite effects. In agreement with this phenotype, IER2 expression was positively correlated with the metastatic potential and integrin β1 (ITGB1) expression in HCC cell lines. Moreover, we demonstrated a critical role for IER2 in regulation of HCC cell‑extracellular matrix (ECM) adhesion and motility by the transcriptionally promoted ITGB1. Furthermore, we showed that ITGB1‑focal adhesion kinase (FAK)‑Src‑paxillin signal pathway activated by IER2 may contribute to the HCC cell‑ECM adhesion and motility. These results demonstrated that IER2 promoted HCC cell adhesion and motility probably by directly increasing ITGB1 expression and subsequently activating the ITGB1‑FAK‑Src‑paxillin signal pathway.

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Abstract. Human immediate early response 2 (IER2) has been characterized as a putative nuclear protein that functions as a transcription factor or transcriptional co-activator in the regulation of cellular responses, and may be involved in the regulation of tumor progression and metastasis. Data from our previous gene expression profile of the human microvascular endothelial cells during capillary morphogenesis showed a significant alteration of IER2 expression, suggesting that IER2 may participate in the regulation of the endothelial cell morphogenesis and angiogenesis. The aim of the present study was to investigate the role of IER2 in cell motility, cell-matrix adhesion and in vitro capillary-like structures formation of the human umbilical vein endothelium cells (HUVECs). IER2 was constitutively expressed in HUVECs, and lentiviral-mediated depletion of IER2 significantly reduced the cell motility, cell-matrix adhesion and capillary-like structures formation of HUVECs. Results also showed that depletion and overexpression of IER2 altered the actin cytoskeleton rearrangement in HUVECs. Furthermore, results from western blot analysis showed that the activity of the focal adhesion kinase (FAK) can be regulated by IER2. These results indicated that IER2 regulates endothelial cell motility, adhesion on collagen type I matrix and the capillary tube formation, as the result of the regulation of the actin cytoskeleton rearrangement presumably via a FAK-dependent mechanism.

Abstract. Accumulating evidence implicates monopolar spindle-one-binder protein (MOB)2 as an inhibitor of nuclear-Dbf2-related kinase (NDR) by competing with MOB1 for interaction with NDR1/2. NDR/large tumor suppressor (LATS) kinases may function similarly to yes-associated protein (YAP) kinases and be considered as members of the Hippo core cassette. MOB2 appears to serve roles in cell survival, cell cycle progression, responses to DNA damage and cell motility. However, the underlying mechanisms involved remain unclarified. In the present study, it was demonstrated that the knockout of MOB2 by clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 promoted migration and invasion, induced phosphorylation of NDR1/2 and decreased phosphorylation of YAP in SMMC-7721 cells when compared with the blank vector-transduced cells. By contrast, the overexpression of MOB2 resulted in the opposite results. Mechanistically, MOB2 regulated the alternative interaction of MOB1 with NDR1/2 and LATS1, which resulted in increased phosphorylation of LATS1 and MOB1 and thereby led to the inactivation of YAP and consequently inhibition of cell motility. The results of the present study provide evidence of MOB2 serving a positive role in LATS/YAP activation by activating the Hippo signaling pathway.

The development of trichomes, which protect plants against herbivores, is affected by various stresses. In tomato, previous studies showed that stress triggered JA signaling influences trichome formation, but the underlying mechanism is not fully resolved. Here, we found two C2H2 zinc finger proteins synergistically regulate JA-induced trichome formation in tomato. The naturally occurring mutations in H and its close homolog H-like gene in a spontaneous mutant, LA3172 cause severely affected trcihome development. Compared with respective single mutant, h/hl double mutant displayed more severe trichome defects in all tissues. Despite the partially redundant function, H and HL genes regulate the trichome formation in the spatially distinct manner, with HL more involved in hypocotyls and leaves, while H more involved in stems and sepals. Furthermore，the activity of H/HL is essential for JA-triggered trichome formation. JA signaling inhibitor SlJAZ2 represses the activity of H and HL via physical interaction, resulting in the activation of THM1, a negative regulator of trichome formation. Our results provide novel insight into the mechanism of the trichome formation in response to stress induced JA signaling in tomato.