Desmosomes

Definition

Desmosomes are specialized cell-cell junctions that mechanically connect adjacent cells, particularly in tissues that experience high levels of mechanical stress, such as the skin. They act as 'spot welds' that hold cells together and provide structural integrity to tissues.

5 Must Know Facts For Your Next Test

1. Desmosomes are found in high concentrations in tissues that experience mechanical stress, such as the skin, heart, and intestines.
2. The desmosomal plaque, a dense protein structure within the cell, anchors the desmosome to the cell's intermediate filament network.
3. Mutations in desmosomal proteins can lead to diseases characterized by impaired cell-cell adhesion, such as certain types of cardiomyopathy and skin disorders.
4. Desmosomes work in conjunction with other cell junctions, such as tight junctions and gap junctions, to maintain tissue integrity and facilitate cell-cell communication.
5. The strength and regulation of desmosomes can be influenced by various signaling pathways, including those involved in cell growth, differentiation, and response to mechanical forces.

Review Questions

• Explain the role of desmosomes in the skin and how they contribute to the skin's function.
  • Desmosomes are particularly abundant in the epidermis of the skin, where they play a crucial role in maintaining the structural integrity of the tissue. By mechanically connecting adjacent keratinocytes, desmosomes provide the skin with the necessary tensile strength to withstand the various stresses and strains it experiences, such as stretching, compression, and shear forces. This helps the skin function as an effective barrier against environmental insults and prevent tissue damage or separation. Additionally, the desmosomal connections between cells contribute to the overall cohesion and organization of the epidermis, which is essential for the skin's barrier and protective properties.
• Describe how the molecular composition and organization of desmosomes contribute to their function.
  • The core structure of desmosomes is composed of transmembrane cadherin proteins, which mediate cell-cell adhesion by interacting with cadherin proteins on adjacent cells. These cadherin proteins are anchored to the cell's intermediate filament network through specialized desmosomal plaque proteins, such as desmoplakin and plakoglobin. This connection to the cytoskeleton allows desmosomes to transmit mechanical forces between cells and provide structural support to the tissue. The specific composition and arrangement of desmosomal proteins, as well as their interactions with other cell junction components, contribute to the overall strength and regulation of desmosomal adhesion, which is crucial for the skin's ability to withstand mechanical stresses.
• Analyze the potential consequences of impaired desmosomal function in the skin and how this might impact the skin's overall structure and barrier properties.
  • Disruptions in desmosomal structure or function can have significant consequences for the skin's integrity and barrier properties. Genetic mutations or environmental factors that affect the expression or organization of desmosomal proteins can lead to diseases characterized by impaired cell-cell adhesion, such as certain types of inherited skin disorders (e.g., pemphigus, ectodermal dysplasias). In these conditions, the weakened desmosomal connections between keratinocytes can result in tissue fragility, blistering, and impaired barrier function. This compromises the skin's ability to protect the body from environmental stressors, pathogens, and fluid loss, potentially leading to increased susceptibility to infection, dehydration, and other health problems. Understanding the critical role of desmosomes in maintaining the structural integrity and barrier properties of the skin is essential for developing effective treatments and management strategies for desmosome-related skin disorders.

Related terms

Cell Junctions: Specialized structures that connect adjacent cells and facilitate communication, adhesion, and structural support within tissues.

Intermediate Filaments: Cytoskeletal proteins that extend from desmosomes into the cell interior, anchoring the desmosome to the cell's structural framework.

Cadherin Proteins: Transmembrane proteins that form the core of the desmosome, mediating cell-cell adhesion by interacting with cadherin proteins on adjacent cells.