Comparison of intra-organellar chaperone capacity for dealing with stress-induced protein unfolding

Jurre Hageman, Michel J. Vos, Maria A. W. H. van Waarde, Harm H. Kampinga*

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    35 Citations (Scopus)

    Abstract

    Molecular chaperones are essential for cells to prevent that partially unfolded proteins form non-functional, toxic aggregates. This requirement is increased when cells experience protein unfolding stresses and such could affect all compartments in the eukaryotic cell. Whether all organelles are equipped with comparable chaperone capacities is largely unknown, mainly due to the lack of suitable reporters that allow such a comparison. Here we describe the development of fluorescent luciferase reporters that are sorted to various cellular locations (nucleus, cytoplasm, endoplasmic reticulum, and peroxisomes) and that differ minimally in their intrinsic thermal stability properties. When heating living cells, the rate of inactivation was most rapid for the nuclear-targeted luciferase, indicating that the nucleus is the most sensitive organelle toward heat-induced denaturing stress. Post-heat re-activation, however, occurred at equal kinetics irrespective of luciferase localization. Also, induction of thermotolerance by a priming heat treatment, that coordinately up-regulates all heat-inducible chaperones, resulted in a transient heat resistance of the luciferase in all organelles in a comparable manner. Overexpression of the main heat-inducible Hsp70 family member, HspA1A, protected only the cytosolic and nuclear, but not the other luciferases. Together, our data suggest that in each compartment investigated, including the peroxisome in which so far no chaperones could be detected, chaperone machines are present and can be induced with activities similar to those present in the cytosolic/nuclear compartment.

    Original languageEnglish
    Pages (from-to)34334-34345
    Number of pages12
    JournalThe Journal of Biological Chemistry
    Volume282
    Issue number47
    DOIs
    Publication statusPublished - 23-Nov-2007

    Keywords

    • HEAT-SHOCK-PROTEIN
    • RED FLUORESCENT PROTEIN
    • ENDOPLASMIC-RETICULUM
    • MAMMALIAN-CELLS
    • MOLECULAR CHAPERONES
    • BINDING-PROTEIN
    • HUMAN HOMOLOG
    • IN-VIVO
    • FIREFLY LUCIFERASE
    • TARGETING SIGNAL

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