• Login as Editor
    View Item 
    •   Yeshiva Academic Institutional Repository
    • Albert Einstein College of Medicine (AECOM)
    • Albert Einstein College of Medicine: Doctoral Dissertations
    • View Item
    •   Yeshiva Academic Institutional Repository
    • Albert Einstein College of Medicine (AECOM)
    • Albert Einstein College of Medicine: Doctoral Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Intracellular sorting of peptide hormone precursors and the mechanism of secretory vesicle formation

    Thumbnail
    Date
    1996
    Author
    Chen, Yeguang
    Metadata
    Show full item record
    Abstract
    This thesis is divided into two related parts: (i) Prohormone processing. Most peptide hormones are synthesized as precursors possessing a propeptide. To test that the propeptide may function in intracellular sorting of prohormones to the trans-Golgi network (TGN), a chimeric construct was made which comprises the signal peptide and proregion of anglerfish prosomatostatin-I (SRIF-I) which is processed in rat pituitary GH{dollar}\sb3{dollar} cells, fused to proSRIF-II which degraded in these cells. When the chimera was expressed in GH{dollar}\sb3{dollar} cells, it was found that the SRIF-I propeptide rescued proSRIF-II from degradation and diverted it to secretory vesicles. The chimera was processed to SRIF-28, the physiological product of proSRIF-II. The SRIF-I propeptide functioned only in cis, but not in trans. These data suggest that the SRIF-I propeptide may possess a sorting signal for sequestration into the secretory pathway rather than functioning as an intramolecular chaperone to promote protein folding. (ii) Secretory vesicle formation from the TGN. ADP-ribosylation factor (ARF), a small GTP-binding protein, regulates the budding of vesicles that mediate endoplasmic reticulum (ER)-to-Golgi and intra-Golgi transport. It also plays an important role in maintaining the morphology of the Golgi apparatus. Using a permeabilized cell system derived from GH{dollar}\sb3{dollar} cells, the recombinant wild type human ARF-1 enhanced secretory vesicle budding about two-fold. A mutant lacking the first 17 N-terminal residues, as well as a mutant in the GDP-binding form did not stimulate vesicle formation. In contrast, a mutant defective in GTP hydrolysis promoted vesicle budding. Strikingly, a synthetic peptide corresponding to the N-terminus of human ARF-1 (amino acids 2-17) stimulated secretory vesicle budding, this is in marked contrast to its inhibitory effect on E.R. to Golgi transport. These data demonstrate that in endocrine cells, ARF-1 and particularly its N-terminus plays an essential role in the formation of secretory vesicles. Preliminary evidence suggests that phospholipase D, a downstream effector of ARF, also plays a essential role in promoting release of secretory vesicles from the TGN.
    Permanent Link(s)
    https://yulib002.mc.yu.edu/login?url=http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqm&rft_dat=xri:pqdiss:9621607
    https://hdl.handle.net/20.500.12202/3650
    Collections
    • Albert Einstein College of Medicine: Doctoral Dissertations [1674]

    Yeshiva University Libraries copyright © 2021  DuraSpace
    YAIR Self-Deposit | YAIR User's Guide | Take Down Policy | Contact Us
    Yeshiva University
     

     

    Browse

    AllCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    Login as Editor

    Statistics

    View Usage Statistics

    Yeshiva University Libraries copyright © 2021  DuraSpace
    YAIR Self-Deposit | YAIR User's Guide | Take Down Policy | Contact Us
    Yeshiva University