MK-STYX, a catalytically inactive phosphatase regulating mitochondrially dependent apoptosis
Natalie M Niemi1, Nathan J Lanning, Jeff A Klomp
1Laboratory of Systems Biology, Van Andel Research Institute, 333 Bostwick Ave. NE, Grand Rapids, MI 49503, USA.
Molecular and Cellular Biology
|January 26, 2011
Summary
Researchers identified MK-STYX, a novel regulator of apoptosis. Its depletion prevents cancer cells from undergoing programmed cell death by blocking mitochondrial outer membrane permeabilization, a key step in apoptosis.
Area of Science:
- Molecular Biology
- Cell Biology
- Cancer Research
Background:
- Apoptosis evasion is a hallmark of many cancers, driving tumorigenesis and treatment resistance.
- Identifying novel regulators of apoptosis is crucial for developing new anti-cancer therapies.
Purpose of the Study:
- To identify novel regulators of apoptosis using a large-scale RNA interference (RNAi) screen.
- To characterize the role of the identified kinase-interacting protein, MK-STYX (STYXL1), in regulating apoptosis.
Main Methods:
- Genome-wide RNA interference (RNAi) screen targeting all human kinases and phosphatases.
- Assessment of MK-STYX (STYXL1) function in apoptosis induction via cellular stressors.
- Analysis of mitochondrial outer membrane permeabilization (MOMP) and cytochrome c release.
Main Results:
- MK-STYX (STYXL1), a catalytically inactive phosphatase, was identified as a novel apoptosis regulator.
- MK-STYX depletion inhibits mitochondrion-dependent apoptosis, mimicking Bax and Bak loss.
- Cells lacking MK-STYX expression fail to release cytochrome c, indicating impaired MOMP.
Conclusions:
- MK-STYX (STYXL1) plays a critical role in regulating mitochondrial outer membrane permeabilization (MOMP).
- MK-STYX functions via a novel mechanism distinct from known MOMP regulators.
- Targeting MK-STYX may offer a new therapeutic strategy for sensitizing cancer cells to apoptosis.
More Related Videos
19:44Enhancement of Apoptotic and Autophagic Induction by a Novel Synthetic C-1 Analogue of 7-deoxypancratistatin in Human Breast Adenocarcinoma and Neuroblastoma Cells with Tamoxifen
Published on: May 30, 2012
07:15Mechanism of Kemeng Fang's Inhibition of Podocyte Apoptosis in Rats with Membranous Nephropathy through the PI3K/AKT Signaling Pathway
Published on: August 23, 2024
Related Concept Videos
01:22PI3K/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...
01:31The 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...
01:17The 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...
01:45Destabilization of Microtubules
The destabilization of microtubules can occur during different stages of the microtubule lifecycle, such as nucleation or elongation. It can take place at either end of the microtubule or in the microtubule lattices as a whole. The lifespan of individual microtubules within a cell varies according to the cell type and stage of the cell cycle. During interphase, the lifespan of the microtubule is about 30 minutes, while during cell division, it is about 15 minutes. In axonal microtubules of...
02:17Microtubule Instability
Microtubules are hollow cylindrical filaments having a diameter of approximately 25 nm and a length that varies from 200 nm to 25 μm. GTP-bound tubulin subunits form αβ-heterodimers for microtubule assembly. These core building blocks interact longitudinally, polymerizing into protofilaments. The protofilaments then interact with one another through lateral bonding forces to form stable cylindrical microtubules. These cylindrical filaments are dynamic as they undergo repeated assembly and...
01:07MAPK Signaling Cascades
Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...