Type I collagen

Diagram of Type I Collagen structure

Type I collagen is the most abundant form of collagen found in the human body. It is a fibrillar collagen, which means it forms long fibers and is a major component of the extracellular matrix in various connective tissues. Type I collagen is primarily found in skin, tendon, ligament, bone, and dentin.

Structure

Type I collagen is a heterotrimer, consisting of two _1(I) chains and one _2(I) chain. These chains are encoded by the COL1A1 and COL1A2 genes, respectively. The triple helix structure of Type I collagen is stabilized by hydrogen bonds and is characterized by a repeating Gly-X-Y sequence, where X and Y are often proline and hydroxyproline.

Function

The primary function of Type I collagen is to provide tensile strength and structural support to tissues. It plays a crucial role in maintaining the integrity of the skin, supporting the framework of bone, and facilitating the attachment of muscles to bones via tendons.

Synthesis

Type I collagen synthesis begins with the transcription of the COL1A1 and COL1A2 genes into mRNA, followed by translation into preprocollagen chains. These chains undergo post-translational modifications, including hydroxylation and glycosylation, before forming a procollagen triple helix. The procollagen is then secreted into the extracellular space, where it is cleaved by specific enzymes to form mature collagen fibrils.

Clinical Significance

Mutations in the genes encoding Type I collagen can lead to various genetic disorders, such as osteogenesis imperfecta, which is characterized by brittle bones. Abnormalities in collagen synthesis or degradation can also contribute to conditions like Ehlers-Danlos syndrome and scleroderma.

Related pages

• Collagen
• Extracellular matrix
• Osteogenesis imperfecta
• Ehlers-Danlos syndrome