MAPT and tauopathy: Interestingly, while full length tau has been detected in the extracellular space, C-terminal cleavage of tau has been shown to enhance its secretion (Plouffe et al., 2012) which could have pathological relevance since some truncated tau species appears to be characteristic of particular tauopathies whereas other tau fragments may be common to several tauopathies (Hanger and Wray, 2010; Kovacech et al., 2010).