Related Experiment Video

Updated: Aug 17, 2026

Heterokaryon Technique for Analysis of Cell Type-specific Localization
09:31

Heterokaryon Technique for Analysis of Cell Type-specific Localization

Published on: March 11, 2011

Two arginine rich domains in the p14ARF tumour suppressor mediate nucleolar localization

H Rizos1, A P Darmanian, G J Mann

  • 1Westmead Institute for Cancer Research, University of Sydney, Westmead Hospital, Westmead NSW 2145, Australia.

Oncogene
|June 29, 2000
PubMed

Insights

The INK4a/ARF locus yields two tumor suppressors, p16INK4a and p14ARF. Human p14ARF requires specific domains for nucleolar localization and tumor suppression, unlike its mouse counterpart.

Area of Science:

  • Molecular Biology
  • Cancer Genetics

Background:

  • The INK4a/ARF locus encodes two tumor suppressors: p16INK4a and p14ARF.
  • These proteins regulate cell cycle via pRB and p53 pathways, respectively.
  • ARF inhibits hdm2, stabilizing p53 and inhibiting cell cycle.

Purpose of the Study:

  • To investigate the domains responsible for human p14ARF nucleolar localization and function.
  • To compare human p14ARF with mouse p19ARF regarding these properties.
  • To examine the impact of mutations in the INK4a/ARF locus on tumor suppressor activity.

Main Methods:

  • Site-directed mutagenesis to identify functional domains.
  • Analysis of protein localization and interactions.
  • Assessment of cell cycle inhibition activity.

Main Results:

  • The amino-terminal domain of p14ARF is sufficient for mouse p19ARF nucleolar localization and function.
  • Human p14ARF requires two arginine-rich domains (amino- and carboxy-terminal) for nucleolar targeting.
  • The amino-terminal domain is crucial for p14ARF-hdm2 binding and cell cycle inhibition.
  • A carboxy-terminal domain within exon 2 is involved in nucleolar localization and is mutated in some melanoma kindreds.

Conclusions:

  • Human p14ARF requires distinct domains for nucleolar localization compared to mouse p19ARF.
  • Mutations in exon 2 of the INK4a/ARF locus can impair both p16INK4a and p14ARF tumor suppressor functions.
  • These findings highlight the complex regulation of p14ARF and its implications in cancer predisposition.

More Related Videos

Identification of Nucleolar Factors During HIV-1 Replication Through Rev Immunoprecipitation and Mass Spectrometry09:38

Identification of Nucleolar Factors During HIV-1 Replication Through Rev Immunoprecipitation and Mass Spectrometry

Published on: June 26, 2019

Quantitative Methods to Study Protein Arginine Methyltransferase 1-9 Activity in Cells08:11

Quantitative Methods to Study Protein Arginine Methyltransferase 1-9 Activity in Cells

Published on: August 7, 2021

Related Concept Videos

Conservation of Protein Domains Over Different Proteins02:26

Conservation of Protein Domains Over Different Proteins

Protein domains are small structurally independent units that are part of a single amino acid chain.  Although these domains are often structurally independent, they may rely on synergistic effects to perform their functions as part of a larger protein. Protein domains may be conserved within the same organism, as well as across different organisms.
A limited set of protein domains often duplicate and recombine during evolution. These domains can be organized in different combinations to form...
The Nucleolus02:55

The Nucleolus

The nucleolus is the most prominent substructure of the nucleus. When it was first discovered, it was considered to be an isolated organelle that forms fibrils and granules. In 1931, the relationship between the nucleolus and chromosomes was first described by Heitz. He observed that the appearance and size of nucleolus varies depending on the stage of the cell cycle. He also noticed constricted regions on different chromosomes clustered together at definite cell cycle stages. These regions,...
Nuclear Protein Sorting01:34

Nuclear Protein Sorting

Nuclear protein sorting is the selective trafficking of histones, polymerases, gene regulatory proteins into the nucleus and exporting RNAs and ribosomes to the cytosol. It is a tightly controlled process that regulates gene expression within a cell.
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
Nuclear Export01:42

Nuclear Export

The nucleus restricts several proteins within and allows others to pass. The restricted proteins possess a nuclear retention sequence or NRS, anchoring them to the nuclear lamins and preventing their transport to the cytosol. The non-restricted proteins, after their synthesis, are transported to their site of action, such as the cytosol or other organelles, with the help of nuclear export signals or NES.
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
Directionality of Nuclear Transport01:42

Directionality of Nuclear Transport

Ras-related nuclear protein or Ran is a small G protein that cycles between its GTP and GDP bound states. Ran specific regulators, a Ran GTPase Activating Protein or RanGAP present in the cytosol and a Ran guanine nucleotide exchange factor or RanGEF present inside the nucleus regulate GTP/GDP exchange. A high concentration of GTP inside the cells, in addition to this asymmetric distribution of  Ran-specific regulators, leads to a higher RanGTP concentration inside the nucleus. This...
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...