Fibril Associated Collagens With Interrupted Triple Helices (FACITs) are a group of proteins that play a crucial role in the structure and function of connective tissues in the body. These proteins belong to a larger family of collagens, which are the most abundant proteins in the extracellular matrix of various tissues.
FACITs are characterized by their unique structure, as they contain interruptions in their triple-helical domain. Unlike other collagens that have uninterrupted triple helices, these interruptions result in the formation of additional domains along the collagen molecule. The interruptions are typically formed by non-collagenous regions, which are rich in cysteine residues. These domains contribute to the functional diversity of FACIT collagens and enable interactions with other molecules or extracellular components.
FACITs are mainly found in specialized tissues such as the cornea, tendons, cartilage, and interstitial matrices. They are involved in supporting and organizing the extracellular matrix, providing mechanical strength to tissues, and regulating cell adhesion. Additionally, they play a role in cell signaling, tissue repair, and modulation of inflammatory responses.
Mutations or disruptions in FACIT collagens can lead to various pathological conditions, including connective tissue disorders such as osteogenesis imperfecta and Ehlers-Danlos syndrome. These conditions are characterized by weakened connective tissues, joint hypermobility, and fragile bones.
In summary, Fibril Associated Collagens With Interrupted Triple Helices (FACITs) are a group of specialized collagens that contribute to the structural integrity of connective tissues, regulate cell interactions, and participate in various physiological processes.
