Related Experiment Video

Updated: Aug 9, 2026

Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death
09:18

Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death

Published on: December 27, 2016

Protein phosphatase 2A activates the proapoptotic function of BAD in interleukin- 3-dependent lymphoid cells by a

C W Chiang1, G Harris, C Ellig

  • 1Department of Pediatrics, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.

Blood
|February 27, 2001
PubMed

Insights

The protein BAD, crucial for apoptosis in hematopoietic cells, is dephosphorylated by PP2A phosphatase. This dephosphorylation, regulated by 14-3-3 binding, triggers cell death when survival factors are absent.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • BAD is a proapoptotic protein within the BCL-2 family, critical for regulating apoptosis in hematopoietic cells.
  • The activity of BAD is controlled by reversible phosphorylation, with dephosphorylation leading to apoptosis upon survival factor deprivation.

Purpose of the Study:

  • To investigate the specific phosphatase responsible for BAD dephosphorylation.
  • To elucidate the role of protein phosphatase 2A (PP2A) in regulating BAD activity and cell survival.

Main Methods:

  • Utilized interleukin-3-dependent FL5.12 lymphoid cells.
  • Employed PP2A-selective inhibitors (okadaic acid, fostriecin) and a PP1-selective inhibitor (tautomycin).
  • Performed cell-free extract assays and analyzed the interaction between BAD and 14-3-3 proteins.

Main Results:

  • PP2A-selective inhibitors prevented BAD dephosphorylation, while PP1 inhibitors did not.
  • BAD phosphatase activity in cell-free extracts was sensitive to PP2A inhibitors but not PP1 inhibitors.
  • Dissociation of 14-3-3 from BAD was necessary for dephosphorylation in vitro.
  • Inhibition of BAD phosphatase activity protected cells expressing wild-type BAD from apoptosis, but not those with a phosphorylation-defective mutant.

Conclusions:

  • PP2A, or a similar enzyme, dephosphorylates BAD.
  • The interaction between PP2A, BAD, and 14-3-3 proteins modulates cytokine-mediated survival and apoptosis in hematopoietic cells.

More Related Videos

Assessing Cellular Target Engagement by SHP2 (PTPN11) Phosphatase Inhibitors08:45

Assessing Cellular Target Engagement by SHP2 (PTPN11) Phosphatase Inhibitors

Published on: July 17, 2020

LPS and ATP-induced Death of PMA-differentiated THP-1 Macrophages and its Validation06:12

LPS and ATP-induced Death of PMA-differentiated THP-1 Macrophages and its Validation

Published on: May 3, 2024

Related Concept Videos

Abnormal Proliferation02:23

Abnormal Proliferation

Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...
The Extrinsic Apoptotic Pathway01:17

The Extrinsic Apoptotic Pathway

The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...
The Intrinsic Apoptotic Pathway01:31

The Intrinsic Apoptotic Pathway

Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
Amplifying Signals via Enzymatic Cascade01:22

Amplifying Signals via Enzymatic Cascade

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
The JAK-STAT Signaling Pathway01:20

The JAK-STAT Signaling Pathway

Several cytokine receptors have tightly bound Janus kinase or JAK proteins attached at their cytosolic tail. Small signaling molecules such as cytokines, growth hormones, or prolactins bind to the cytokine receptors and initiate their dimerization. The dimerization brings the cytosolic JAKs together that trans-phosphorylate and activates each other. The activated JAKs now phosphorylate cytosolic tails of the cytokine receptors, which serve as binding sites for adaptor proteins such as  SH2...
PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/mTOR/AKT Signaling Pathway

The mammalian target of rapamycin  (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1  (mTORC1) and mTOR complex 2  (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast,  mTORC2 consists of a rapamycin-insensitive companion...