title: Spatial mapping of the neurite and soma proteomes reveals a functional Cdc42/Rac regulatory network.
abstract: Neurite extension and growth cone navigation are guided by extracellular cues that control cytoskeletal rearrangements. However, understanding the complex signaling mechanisms that mediate neuritogenesis has been limited by the inability to biochemically separate the neurite and soma for spatial proteomic and bioinformatic analyses. Here, we apply global proteome profiling in combination with a neurite purification methodology for comparative analysis of the soma and neurite proteomes of neuroblastoma cells. The spatial relationship of 4,855 proteins were mapped, revealing networks of signaling proteins that control integrins, the actin cytoskeleton, and axonal guidance in the extending neurite. Bioinformatics and functional analyses revealed a spatially compartmentalized Rac/Cdc42 signaling network that operates in conjunction with multiple guanine-nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) to control neurite formation. Interestingly, RNA interference experiments revealed that the different GEFs and GAPs regulate specialized functions during neurite formation, including neurite growth and retraction kinetics, cytoskeletal organization, and cell polarity. Our findings provide insight into the spatial organization of signaling networks that enable neuritogenesis and provide a comprehensive system-wide profile of proteins that mediate this process, including those that control Rac and Cdc42 signaling.
authors.affiliation: Department of Pathology and Moores Cancer Center, University of California at San Diego, La Jolla, CA 92093, USA.
authors.forename: Olivier C
authors.initials: OC
authors.lastname: Pertz
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Laurie J
authors.initials: LJ
authors.lastname: Gay
authors.forename: Marina A
authors.initials: MA
authors.lastname: Gristenko
authors.forename: Therese R
authors.initials: TR
authors.lastname: Clauss
authors.forename: David J
authors.initials: DJ
authors.lastname: Anderson
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Auberry
authors.forename: David G
authors.initials: DG
authors.lastname: Camp
authors.forename: Richard D
authors.initials: RD
authors.lastname: Smith
authors.forename: Richard L
authors.initials: RL
authors.lastname: Klemke
mesh_terms: D045744:Cell Line, Tumor; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D006801:Humans; D016501:Neurites; D020543:Proteome; D034622:RNA Interference; D015398:Signal Transduction; D020764:cdc42 GTP-Binding Protein / Q000502:physiology*; D020744:rac GTP-Binding Proteins / Q000502:physiology*; D020741:rho GTP-Binding Proteins / Q000378:metabolism
chemical_list: D020662:Guanine Nucleotide Exchange Factors; D020543:Proteome; D020764:cdc42 GTP-Binding Protein; D020744:rac GTP-Binding Proteins; D020741:rho GTP-Binding Proteins