Strain amplification and integrin based signaling in osteocytes.

Recent morphological studies have suggested that osteocyte processes are directly attached at discrete locations along the canalicular wall by beta3 integrins at the apex of infrequent, previously unrecognized, canalicular projections. This discovery has led to a new paradigm for the initiation of intracellular signaling, which provides a possible long sought after molecular mechanism for the initiation of intracellular signaling in bone cells. The quantitative feasibility of this hypothesis is explored with a detailed theoretical model, which predicts that axial strains due to the sliding of actin microfilaments about the fixed integrin attachments are in order of magnitude larger than the radial strains in the previously proposed strain amplification theory and two orders of magnitude greater than whole tissue strains.