Related Experiment Video

Updated: Oct 11, 2026

Analysis of Cell Cycle Position in Mammalian Cells
12:19

Analysis of Cell Cycle Position in Mammalian Cells

Published on: January 21, 2012

The expression of p18INK4 and p27kip1 cyclin-dependent kinase inhibitors is regulated differently during human B cell

N Schrantz1, G E Beney, M T Auffredou

  • 1Institut National de la Santé et de la Recherche Médicale, Unité 131, and Centre de Recherche Claude Bernard, Clamart, France.

Journal of Immunology (Baltimore, Md. : 1950)
|October 18, 2000
PubMed

Insights

Two cyclin-dependent kinase inhibitors, p27(Kip1) and p18(INK4c), regulate distinct stages of human B lymphocyte activation. p27(Kip1) controls cell cycle entry, while p18(INK4c) mediates early G(1) arrest for terminal differentiation.

Area of Science:

  • Immunology
  • Cell Biology
  • Molecular Biology

Background:

  • Cell cycle progression is regulated by cyclin-dependent kinases (cdks) and their inhibitors.
  • Human B lymphocyte activation involves complex regulatory mechanisms controlling cell division and differentiation.

Purpose of the Study:

  • To investigate the differential roles of p27(Kip1) and p18(INK4c) in human B lymphocyte activation.
  • To elucidate the specific cell cycle phases controlled by these two cdk inhibitors.

Main Methods:

  • Analysis of p27(Kip1) and p18(INK4c) expression in human B cells stimulated in vitro and in vivo.
  • Assessment of cell cycle progression and immunoglobulin (Ig) production.
  • Investigation of cyclin D3/cdk6-mediated retinoblastoma protein phosphorylation.

Main Results:

  • Resting B cells express high p27(Kip1) and no p18(INK4c).
  • In vitro stimulation decreases p27(Kip1), promoting cell cycle entry.
  • Ig production correlates with p18(INK4c) expression and early G(1) arrest, inhibiting cyclin D3/cdk6 activity.

Conclusions:

  • p27(Kip1) and p18(INK4c) play distinct roles in B lymphocyte activation.
  • p27(Kip1) is crucial for initiating cell cycle entry.
  • p18(INK4c) is essential for early G(1) arrest, facilitating terminal B lymphocyte differentiation.

More Related Videos

In Vitro Differentiation Model of Human Normal Memory B Cells to Long-lived Plasma Cells10:26

In Vitro Differentiation Model of Human Normal Memory B Cells to Long-lived Plasma Cells

Published on: January 20, 2019

Related Concept Videos

Inhibition of Cdk Activity02:34

Inhibition of Cdk Activity

The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...
Positive Regulator Molecules02:39

Positive Regulator Molecules

Mitotic cell division results in daughter cells that exactly resemble the parent cell. However, errors in the DNA replication or distribution of genetic material may lead to genetic mutations that may be passed down to every new cell formed from the resulting abnormal cell. Propagation of such mutant cells is restricted through checkpoint mechanisms present at different stages of the cell cycle. These checkpoints involve regulator molecules that either promote or demote cell cycle events.
Positive Regulator Molecules01:45

Positive Regulator Molecules

To consistently produce healthy cells, the cell cycle—the process that generates daughter cells—must be precisely regulated.
Negative Regulator Molecules01:23

Negative Regulator Molecules

Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.
Molecular Factors Affecting Cell Division01:27

Molecular Factors Affecting Cell Division

Several external and internal factors influence the initiation and inhibition of cell division. For instance, the death of nearby cells or the release of human growth hormone (hGH) promotes cell division. In contrast, lack of hGH or crowding of cells can inhibit cell division.
Several proteins function as internal regulators to ensure each cell cycle stage is completed faithfully before proceeding to the next. Regulator molecules may act directly or influence the activity or production of other...
The Cell Cycle Control System01:28

The Cell Cycle Control System

The cell cycle regulation directs how a cell proceeds from one phase to the next and begins mitosis. The cell cycle control system includes intracellular regulatory molecules and external triggers. They provide "stop" or "advance" signals and operate at specific cell cycle stages termed checkpoints to ensure that a particular process is completed before the cell advances to the next phase.
Cyclins and cyclin-dependent kinases (Cdks) are the primary cell cycle regulators and function at the cell...