FACIT collagens, also known as fibril-associated collagens with interrupted triple helices, refer to a subset of collagens that play a crucial role in the formation and organization of connective tissues in vertebrates. Collagens are a family of structural proteins that provide strength and support to various tissues in the body, including skin, bones, tendons, and cartilage.
The term FACIT collagens stems from their distinct structural features. Unlike typical collagen molecules, FACIT collagens possess interruption sequences within their triple helical domains, which are regions comprising three intertwined polypeptide chains called alpha chains. These interruptions consist of non-triple helical sequences that lead to a kink in the collagen molecule's structure. This unique feature confers additional flexibility to FACIT collagens, enabling them to interact with and regulate the formation of collagen fibrils.
FACIT collagens are primarily found in association with collagen fibrils, which are long, rope-like structures formed by the aggregation of collagen molecules. They contribute to the organization and stability of fibrils, thereby influencing the mechanical properties of connective tissues. Moreover, FACIT collagens play a role in the binding of other proteins and cells within the extracellular matrix, facilitating cellular adhesion and tissue maintenance.
Overall, FACIT collagens represent a specialized group of collagens that contribute to the structural integrity and function of connective tissues. Their unique interrupted triple helical structure allows for enhanced flexibility and interactions with other molecules in the extracellular matrix, thereby playing a crucial role in tissue organization and maintenance.
