COMP - Cartilage Oligomeric Matrix Protein | Elisa - Clia - Antibody - Protein

Background:

Cartilage Oligomeric Matrix Protein (COMP), also known as thrombospondin-5 (TSP-5), is a protein that in humans is encoded by the COMP gene. COMP is a non-collagenous extracellular matrix protein primarily found in cartilage, tendon, and ligament tissues. It belongs to the thrombospondin family of extracellular matrix glycoproteins. COMP plays a crucial role in maintaining the structural integrity of these tissues. It interacts with other extracellular matrix proteins such as collagen and fibronectin, contributing to the stability and organization of the extracellular matrix. Additionally, COMP is involved in cell signaling processes and may regulate cell adhesion, migration, and proliferation. Mutations in the COMP gene are associated with certain skeletal dysplasias and osteoarthritis. These conditions can lead to abnormalities in bone and cartilage development, resulting in skeletal deformities and joint problems.

Protein Structure:

• Primary Structure: COMP is a large glycoprotein composed of 757 amino acids.
• Secondary Structure: The protein contains several distinct domains, including an N-terminal coiled-coil domain, four EGF-like (epidermal growth factor-like) repeats, eight TSP type-3 repeats, and a C-terminal globular domain.
• Tertiary and Quaternary Structure: COMP is a pentamer, meaning five COMP molecules assemble into a single functional unit. This pentameric structure is stabilized through interchain disulfide bonds and is essential for its function in the extracellular matrix.

Classification and Subtypes:

COMP is classified as a matricellular protein, which means it is an extracellular matrix protein that influences cell-matrix interactions and cell behavior. Although COMP itself does not have subtypes, its functions and interactions can vary depending on the tissue type and the extracellular matrix composition.

Function and Biological Significance:

• Structural Role: COMP contributes to the organization and stability of the cartilage extracellular matrix by interacting with collagen and other matrix proteins. It helps to maintain the integrity and resilience of cartilage tissue.
• Cellular Interactions: COMP binds to cell surface receptors, such as integrins, influencing cell attachment, proliferation, and differentiation.
• Chondrocyte Function: COMP is involved in the regulation of chondrocyte function, including their proliferation and matrix synthesis.
• Mechanical Properties: COMP enhances the mechanical properties of cartilage, providing resistance to compressive forces and contributing to the tissue’s elasticity.

Interactions:

• Collagen: COMP interacts with collagen types I, II, and IX, playing a crucial role in the organization of collagen fibrils in cartilage.
• Integrins: Through its interaction with integrins on the cell surface, COMP influences cell adhesion, migration, and signal transduction pathways.
• Matrix Proteins: COMP interacts with other extracellular matrix proteins, such as fibronectin and matrilin-3, contributing to matrix assembly and stability.

Clinical Issues:

• Pseudachondroplasia (PSACH): Mutations in the COMP gene cause PSACH, a genetic disorder characterized by short stature and joint problems due to abnormal cartilage and bone development.
• Multiple Epiphyseal Dysplasia (MED): Mutations in COMP also cause MED, a condition that affects the development of long bones, leading to joint pain and deformities.
• Osteoarthritis: Elevated levels of COMP are found in the synovial fluid and serum of patients with osteoarthritis, making it a potential biomarker for the diagnosis and progression of the disease.
• Skeletal Dysplasias: Other skeletal disorders may be associated with COMP abnormalities, highlighting its importance in cartilage and bone biology.

Summary:

Cartilage Oligomeric Matrix Protein (COMP) is a critical extracellular matrix protein essential for maintaining the structural and functional integrity of cartilage. Its interactions with collagen and other matrix proteins are vital for the resilience and mechanical properties of cartilage tissue. Mutations in the COMP gene can lead to various skeletal disorders, including pseudachondroplasia and multiple epiphyseal dysplasia. Understanding COMP's role in cartilage biology and its clinical implications can provide insights into the development and treatment of cartilage-related diseases.