PACSINs are a protein family consisting of three members that have been implicated in synaptic vesicular membrane trafficking and regulation of dynamin-mediated endocytotic processes (Cuajungco, 2006). It is presumed that all isoforms bind Dynamin, Synaptojanin 1 and N-WASP through their Src homology 3 domains. While PACSIN1 appears to be restricted to neural tissues, two PACSINs are more widespread with PACSIN2 being ubiquitously expressed and PACSIN3 present mainly in skeletal muscle, heart and lung (Modregger, 2001). PACSIN3 (protein kinase C and casein kinase substrate in neurons 3) contains a short proline-rich region and lacks asparagine-proline-phenylalanine motifs, that differentiates it from the rest of the PACSIN family. Expected molcular weight is 49 kDa.