Neurobiology of Disease APP Anterograde Transport Requires Rab 3 A GTPase Activity for Assembly of the Transport Vesicle

The amyloid precursor protein (APP) is anterogradely transported by conventional kinesin in a distinct transport vesicle, but both the biochemical composition of such a vesicle and the specific kinesin-1 motor responsible for transport are poorly defined. APP may be sequentially cleaved by betaand gamma-secretases leading to accumulation of beta-amyloid (Abeta) peptides in brains of Alzheimer's disease patients, whereas cleavage of APP by alpha-secretases prevents Abeta generation. Here, we demonstrate by time-lapse analysis and immunoisolations that APP is a cargo of a vesicle containing the kinesin heavy chain isoform kinesin-1C, the small GTPase Rab3A, and a specific subset of presynaptic protein components. Moreover, we report that assembly of kinesin-1C and APP in this vesicle type requires Rab3A GTPase activity. Finally, we show cleavage of APP in transport vesicles by alpha-secretase activity, likely mediated by ADAM10. Together, these data indicate that maturation of APP transport vesicles, including recruitment of conventional kinesin, requires Rab3 GTPase activity. Neurobiology of Disease APP Anterograde Transport Requires Rab3A GTPase Activity for Assembly of the Transport Vesicle Anita Szodorai,2 Yung-Hui Kuan,2,9 Silke Hunzelmann,1,2 Ulrike Engel,4 Ayuko Sakane,6 Takuya Sasaki,6 Yoshimi Takai,7 Joachim Kirsch,3 Ulrike Müller,5 Konrad Beyreuther,2,10 Scott Brady,8 Gerardo Morfini,8 and Stefan Kins1,2 1Technical University of Kaiserslautern, Department of Human Biology and Human Genetics, D-67663 Kaiserslautern, Germany, 2Centre for Molecular Biology, 3Department of Anatomy and Cell Biology, 4Nikon Imaging Center, Bioquant, and 5Institute for Pharmacia and Molecular Biotechnology, University of Heidelberg, D-69120 Heidelberg, Germany, 6Department of Biochemistry, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan, 7Division of Molecular and Cellular Biology and Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine/Faculty of Medicine, Kobe 650-0017, Japan, 8Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, Illinois 60612, 9Max Planck Institute for Brain Research, D-60528 Frankfurt, Germany, and 10Network Aging Research, D-69115 Heidelberg, Germany The amyloid precursor protein (APP) is anterogradely transported by conventional kinesin in a distinct transport vesicle, but both the biochemical composition of such a vesicle and the specific kinesin-1 motor responsible for transport are poorly defined. APP may be sequentially cleaved by and -secretases leading to accumulation of -amyloid (A ) peptides in brains of Alzheimer’s disease patients, whereas cleavage of APP by -secretases prevents A generation. Here, we demonstrate by time-lapse analysis and immunoisolations that APP is a cargo of a vesicle containing the kinesin heavy chain isoform kinesin-1C, the small GTPase Rab3A, and a specific subset of presynaptic protein components. Moreover, we report that assembly of kinesin-1C and APP in this vesicle type requires Rab3A GTPase activity. Finally, we show cleavage of APP in transport vesicles by -secretase activity, likely mediated by ADAM10. Together, these data indicate that maturation of APP transport vesicles, including recruitment of conventional kinesin, requires Rab3 GTPase activity.