contact inhibition

Definition

Target type: biologicalprocess

The series of events in which information about the density of cells in a population is received by direct cell-cell contact and is converted into a molecular signal, resulting in the cessation of cell growth or proliferation. [GOC:dph, PMID:17376520]

Contact inhibition is a fundamental process in multicellular organisms that regulates cell growth and movement. It prevents cells from growing uncontrollably and invading surrounding tissues, contributing to the maintenance of tissue homeostasis and preventing tumor formation. Here's a detailed description of the biological process:

**1. Cell-Cell Contact:** The process begins with the physical interaction between cells. As cells grow and divide, they come into contact with neighboring cells. This contact triggers signaling pathways within the cells, leading to changes in their behavior.

**2. Signaling Pathways:** Several signaling pathways are involved in contact inhibition, including:
* **Cadherin-mediated cell adhesion:** Cadherins are transmembrane proteins that mediate cell-cell adhesion. When cells come into contact, cadherins bind to each other, forming a strong adhesive junction. This binding activates downstream signaling pathways.
* **Growth Factor Signaling:** Contact inhibition can also involve the downregulation of growth factors, such as epidermal growth factor (EGF). When cells are in contact, they may secrete less growth factor, or the growth factor receptors on the cell surface may become less sensitive to the factor.
* **Other signaling pathways:** Other signaling pathways, such as the Hippo pathway and the Ras pathway, can also contribute to contact inhibition.

**3. Cell Cycle Arrest:** One of the key outcomes of contact inhibition is cell cycle arrest. When cells are in contact, they typically enter the G1 phase of the cell cycle, where they cease dividing and remain in a quiescent state. This arrest is mediated by the regulation of key cell cycle proteins, such as cyclin-dependent kinases (CDKs) and their inhibitors.

**4. Changes in Cell Morphology:** In addition to cell cycle arrest, contact inhibition can also lead to changes in cell morphology. For example, cells may become more flattened or elongated, and their cytoskeletal organization may be altered. These changes can affect cell movement and migration.

**5. Role in Development and Cancer:** Contact inhibition is crucial for normal development and tissue homeostasis. During embryonic development, contact inhibition ensures that cells grow and divide in an organized manner, forming the correct tissues and organs. In adults, contact inhibition helps to maintain the integrity of tissues and prevent uncontrolled cell growth. When contact inhibition is disrupted, it can contribute to the development of cancer. Cancer cells often lose their ability to respond to contact inhibition, allowing them to grow uncontrollably and invade surrounding tissues.

**6. Role in Wound Healing:** While contact inhibition typically inhibits cell growth, it can also play a role in wound healing. In the early stages of wound healing, cells may migrate to the wound site without being inhibited by contact, allowing for rapid closure of the wound. Once the wound is closed, contact inhibition is re-established to prevent excessive scarring.'
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Proteins (3)

Compounds (57)