title: The alternative TrkAIII splice variant targets the centrosome and promotes genetic instability.
abstract: The hypoxia-regulated alternative TrkAIII splice variant expressed by human neuroblastomas exhibits oncogenic potential, driven by in-frame exon 6 and 7 alternative splicing, leading to omission of the receptor extracellular immunoglobulin C(1) domain and several N-glycosylation sites. Here, we show that the TrkAIII oncogene promotes genetic instability by interacting with and exhibiting catalytic activity at the centrosome. This function depends upon intracellular TrkAIII accumulation and spontaneous interphase-restricted activation, in cytoplasmic tyrosine kinase (tk) domain orientation, predominantly within structures that closely associate with the fully assembled endoplasmic reticulum intermediate compartment and Golgi network. This facilitates TrkAIII tk-mediated binding of gamma-tubulin, which is regulated by endogenous protein tyrosine phosphatases and geldanamycin-sensitive interaction with Hsp90, paving the way for TrkAIII recruitment to the centrosome. At the centrosome, TrkAIII differentially phosphorylates several centrosome-associated components, increases centrosome interaction with polo kinase 4, and decreases centrosome interaction with separase, the net results of which are centrosome amplification and increased genetic instability. The data characterize TrkAIII as a novel internal membrane-associated centrosome kinase, unveiling an important alternative mechanism to "classical" cell surface oncogenic receptor tk signaling through which stress-regulated alternative TrkAIII splicing influences the oncogenic process.
authors: Department of Experimental Medicine, University of L'Aquila, L'Aquila, Italy.
authors: Antonietta Rosella
authors: AR
authors: Farina
authors: Antonella
authors: A
authors: Tacconelli
authors: Lucia
authors: L
authors: Cappabianca
authors: Gesilia
authors: G
authors: Cea
authors: Sonia
authors: S
authors: Panella
authors: Antonella
authors: A
authors: Chioda
authors: Alessandra
authors: A
authors: Romanelli
authors: Carlo
authors: C
authors: Pedone
authors: Alberto
authors: A
authors: Gulino
authors: Andrew Reay
authors: AR
authors: Mackay
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D018385:Centrosome / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D005091:Exons; D042822:Genomic Instability; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D051379:Mice; D009447:Neuroblastoma / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D020917:Receptor, trkA / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D064247:Separase; D015398:Signal Transduction / Q000502:physiology; D014404:Tubulin / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D014404:Tubulin; C056608:caltractin; C088051:Plk4 protein, mouse; D020917:Receptor, trkA; D017346:Protein Serine-Threonine Kinases; D010450:Endopeptidases; C577987:ESPL1 protein, human; D064247:Separase