title: Carboxypeptidase E cytoplasmic tail-driven vesicle transport is key for activity-dependent secretion of peptide hormones.
abstract: Vesicular transport of peptide hormones from the cell body to the plasma membrane for activity-dependent secretion is important for endocrine function, but how it is achieved is unclear. Here we uncover a mechanism in which the cytoplasmic tail of transmembrane carboxypeptidase E (CPE) found in proopiomelanocotin (POMC)/ACTH vesicles interacts with microtubule-based motors to control transport of these vesicles to the release site in pituitary cells. Overexpression of the CPE tail in live cells significantly reduced the velocity and distance of POMC/ACTH- and CPE-containing vesicle movement into the cell processes. Biochemical studies showed that the CPE tail interacted with dynactin, which, in turn, recruited microtubule plus-end motors kinesin 2 and kinesin 3. Overexpression of the CPE tail inhibited the stimulated secretion of ACTH from AtT20 cells. Thus, the CPE cytoplasmic tail interaction with dynactin-kinesin 2/kinesin 3 plays an important role in the transport of POMC vesicles for activity-dependent secretion.
authors.affiliation: Section on Cellular Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Park
authors.forename: Niamh X
authors.initials: NX
authors.lastname: Cawley
authors.forename: Y Peng
authors.initials: YP
authors.lastname: Loh
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D043423:Carboxypeptidase H / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D022162:Cytoplasmic Vesicles / Q000378:metabolism*; D000072159:Dynactin Complex; D047468:Immunoprecipitation; D016547:Kinesins / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D036361:Peptide Hormones / Q000378:metabolism*; D011333:Pro-Opiomelanocortin / Q000378:metabolism; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid
chemical_list: D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins; D036361:Peptide Hormones; D011333:Pro-Opiomelanocortin; D000324:Adrenocorticotropic Hormone; D043423:Carboxypeptidase H; D016547:Kinesins