Protein Kinase C And Casein Kinase Substrate In Neurons 1 (PACSIN1)

PACSIN1 is 95% identical to the mouse protein, contains a conserved N-terminal Fes/CIP4 homology (FCH) domain (also called the RAEYL motif), a central coiled-coil region, and a C-terminal SH3 motif. Northern blot analysis revealed strong expression of a 4.4-kb PACSIN1 transcript in brain, with much lower levels in heart, pancreas, and liver. Normally, PACSIN1 is located along neurites and within synaptic boutons, but in HD patient neurons there was a progressive loss of PACSIN1 immunostaining in synaptic varicosities, beginning in presymptomatic and early-stage HD. Further, PACSIN1 immunostaining of HD patient tissue revealed a more cytoplasmic distribution of the protein, with particular concentration in the perinuclear region coincident with mutant huntingtin.