Related Experiment Video
Updated: Jul 21, 2026

Engineering Artificial Factors to Specifically Manipulate Alternative Splicing in Human Cells
Published on: April 26, 2017
Contribution of guanine exchange factor H1 in phorbol ester-induced apoptosis
1Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, No. 1 Section 1 Jen-Ai Road, Taipei, Taiwan, ROC.
Abstract:
Phorbol-12-myristate-13-acetate (PMA) treatment induces erythroblastoma D2 cells kept in suspension to undergo RhoA-dependent contraction and to become proapoptotic, while attached cells are induced to differentiate accompanied by the reduction of RhoA activity. In this study, we found that guanine exchange factor H1 (GEF-H1) is highly expressed in D2 cells. Depletion of GEF-H1 expression in D2 cells decreased RhoA activity and prevented PMA-induced contraction and apoptosis. Upon PMA stimulation, GEF-H1 became associated with microtubules in cells that were induced to differentiate. As a contrast, in the proapoptotic population of cells GEF-H1 stayed in the cytoplasm without showing PMA-responsive microtubule translocation. Given that GEF-H1 is inactivated when associated with microtubules and its release into cytosol due to depolymerization of microtubules activates RhoA, our results demonstrated that nonmicrotubule-associated GEF-H1 in D2 cells contributes to the sustained activation of RhoA/ROCK signaling in suspension cells, making cells susceptible to PMA-induced apoptosis.
More Related Videos
09:18Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death
Published on: December 27, 2016
05:28Monitoring On-Target Signaling Responses in Larval Zebrafish - Z-REX Unmasks Precise Mechanisms of Electrophilic Drugs and Metabolites
Published on: June 2, 2023
Related Concept Videos
GTPases and their Regulation
Large G-proteins, also known...
The Extrinsic Apoptotic Pathway
The Intrinsic Apoptotic Pathway
Phagocytosis of Apoptotic Cells
Normal cells contain receptors that prevent them from being recognized by phagocytes.
Amplifying Signals via Enzymatic Cascade
Small GTPases - Ras and Rho
Three regulatory proteins control their activity: