Extracellular matrix remodeling through endocytosis and resurfacing of Tenascin-R

SummaryThe brain extracellular matrix (ECM) assembles around neurons and synapses, and is thought to change only rarely, through proteolysis and renewed protein synthesis. We report here an alternative ECM remodeling mechanism, based on the recycling of ECM molecules. We found that a key ECM protein, Tenascin-R, is frequently endocytosed, and later resurfaces, preferentially near synapses. The TNR molecules complete this cycle within ∼3 days, in an activity-dependent fashion.