Related Experiment Video

Updated: Jul 20, 2026

In Vivo Detection and Analysis of Rb Protein SUMOylation in Human Cells
09:40

In Vivo Detection and Analysis of Rb Protein SUMOylation in Human Cells

Published on: November 2, 2017

Apoptin is modified by SUMO conjugation and targeted to promyelocytic leukemia protein nuclear bodies

K Janssen1, T G Hofmann, D A Jans

  • 1Institute of Molecular Medicine, Heinrich-Heine-University, Düsseldorf, Germany.

Oncogene
|August 23, 2006
PubMed

Insights

Chicken anemia virus (CAV) apoptin protein shows potential as an anticancer therapeutic by inducing tumor cell death. It selectively targets cancer cells, independent of promyelocytic leukemia (PML) protein interactions, suggesting a novel cancer treatment pathway.

Area of Science:

  • Oncology
  • Virology
  • Molecular Biology

Background:

  • Apoptin, derived from chicken anemia virus (CAV), exhibits selective toxicity towards tumor cells, inducing apoptosis.
  • The precise mechanism of apoptin's tumor cell selectivity and its cellular localization are not fully understood.

Purpose of the Study:

  • To investigate the interaction of apoptin with promyelocytic leukemia (PML) protein and PML nuclear bodies (NBs).
  • To elucidate the role of apoptin sumoylation in its cellular localization and tumoricidal activity.
  • To determine if PML is essential for apoptin-mediated tumor cell killing.

Main Methods:

  • Co-immunoprecipitation assays to detect apoptin-PML interaction.
  • Confocal microscopy to visualize cellular localization of apoptin and PML NBs.
  • Analysis of sumoylation-deficient apoptin mutants.
  • Apoptosis assays in various cell lines, including PML-deficient cells.

Main Results:

  • Apoptin directly interacts with PML and accumulates in PML NBs in tumor cells.
  • Apoptin undergoes sumoylation, and this modification is crucial for its recruitment to PML NBs.
  • A sumoylation-deficient apoptin mutant localizes to the nuclear matrix, fails to bind PML, but retains full apoptotic activity.
  • Apoptin effectively kills tumor cells irrespective of PML expression levels or functional PML NBs.

Conclusions:

  • Apoptin induces tumor cell apoptosis independently of PML and sumoylation.
  • The interaction between apoptin, PML, and SUMO proteins may be significant for CAV replication, but not for apoptin's anticancer efficacy.

More Related Videos

Localization of SUMO-modified Proteins Using Fluorescent Sumo-trapping Proteins06:23

Localization of SUMO-modified Proteins Using Fluorescent Sumo-trapping Proteins

Published on: April 27, 2019

In Vitro SUMOylation Assay to Study SUMO E3 Ligase Activity09:45

In Vitro SUMOylation Assay to Study SUMO E3 Ligase Activity

Published on: January 29, 2018

Related Concept Videos

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...
Phagocytosis of Apoptotic Cells01:17

Phagocytosis of Apoptotic Cells

Cells undergoing apoptosis form apoptotic bodies that must be removed immediately to prevent inflammation, autoimmune diseases, and necrosis. Phagocytosis is carried out by professional phagocytes such as macrophages or  immature dendritic cells. Non-professional phagocytes such as  epithelial cells and fibroblasts also take part in this process; however, they are not as effective as professional phagocytes. 
Normal cells contain receptors that prevent them from being recognized by phagocytes.
Regulation of Nuclear Protein Sorting01:45

Regulation of Nuclear Protein Sorting

Nuclear protein sorting regulates nucleus composition and gene expression, crucial for determining the fate of a eukaryotic cell. Hence, the entry and exit of molecules across the nuclear envelope is a tightly controlled process. Nuclear protein sorting can be inhibited by one of the following ways: 1) masking cargo signal sequences, 2) modifying the nuclear receptor's affinity for cargo, 3) controlling the nuclear pore size, 4) retaining the cargo during its transit to the cytosol or the...
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...
Apoptosis01:30

Apoptosis

Apoptosis is a combination of two Greek words, 'apo' and 'ptosis,' meaning separation and falling off, respectively. Hippocrates used this word to describe gangrene, which was caused due to bandaging of fractured bones. Apoptosis was distinguished from necrosis in 1970 when John Kerr reported observations of morphological changes occurring during apoptosis. During one experiment, he observed that the disruption of blood supply to the liver tissue resulted in a size reduction of the tissue.
Covalently Linked Protein Regulators02:04

Covalently Linked Protein Regulators

Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein.