Bookshelf

Hypothetical Sequence of the Fibrillin Assembly Steps into Microfibrils. Various cell types such as fibroblasts or smooth muscle cells synthesize and secrete fibrillin. Processing of the terminal ends by furin/PACE type proteases occur either intra- or extracellularly (I). Processed molecules interact with cell surface proteoglycans (light gray ellipses) or integrins (dark grey ellipses) for alignment and concentration (II). Homotypic fibrillin-1 and/or heterotypic fibrillin-1/fibrillin-2 interaction occur at the terminal ends followed by reducible (disulfide bonds) and nonreducible transglutaminase mediated cross-link formation (III). Elongation is mediated through the central parts of the fibrillin molecules (IV) leading to an observable fibrillin network by indirect immunofluorescence. Further maturation events lead to the “beads-on-a-string” microfibrils and finally to tissue microfibrils (V).