title: Clathrin heavy chain gene fusions expressed in human cancers: analysis of cellular functions.
abstract: Clathrin is a protein expressed ubiquitously that has important functions in membrane trafficking and mitosis. Two different gene fusions involving clathrin heavy chain (CHC) have been described in human cancers. These involve either anaplastic lymphoma kinase (ALK) or transcription factor binding to IGHM enhancer 3 (TFE3) and raise the possibility that altered clathrin function in cells expressing the fusion proteins could contribute to oncogenesis. In the present study, we tested the functions of CHC-ALK and CHC-TFE3 in endocytosis and mitosis. CHC-ALK is comparable to full-length CHC in both functions indicating that malignant transformation in cells expressing CHC-ALK is not because of any change in clathrin function. CHC-TFE3 is not functional in endocytosis, but can substitute for CHC in mitosis. CHC-TFE3 causes prolonged interphase that is attributed to the TFE3 portion of the protein. We also describe how CHC-TFE3 is a dimer. This suggests that clathrin's proposed role in intermicrotubule bridging can be fulfilled not only by trimers but also by dimers. Finally, this study shows that the membrane trafficking and mitotic functions of clathrin are independent and separable.
authors.affiliation: Physiological Laboratory and Cancer Research UK Centre, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK.
authors.forename: Maria K E
authors.initials: MK
authors.lastname: Blixt
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Royle
mesh_terms: D000077548:Anaplastic Lymphoma Kinase; D000818:Animals; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology; D033922:Clathrin Heavy Chains / Q000235:genetics* / Q000378:metabolism*; D050939:Gene Fusion; D057809:HEK293 Cells; D006801:Humans; D008870:Microtubules / Q000378:metabolism; D009369:Neoplasms / Q000235:genetics* / Q000378:metabolism; D055503:Protein Multimerization; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; C069203:TFE3 protein, human; D033922:Clathrin Heavy Chains; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases