A microfibril is a very fine fibril, or fiber-like strand, consisting of glycoproteins and cellulose.
It is usually, but not always, used as a general term in describing the structure of protein fiber, e.g. hair and sperm tail.
During the assembly, mirofibrils exhibit a repeating stringed-beads arrangement produced by the cross-linking of molecules forming a striated pattern with a given periodicity when viewed stained under an electron microscope.
Formation of fibrillin microfibrils in the pericellular region affects the activity of a growth factor called TGFβ.
[1] In Marfan syndrome, a connective tissue disorder, mutations in the gene encoding for the fibrillin-1 protein impact nearly every one of its domains.