Abstract
The heat shock proteins (HSP) are a highly conserved family of proteins with critical functions in protein folding, protein trafficking, and cell signaling. These proteins also protect the cell against injury. HSP60 has been found in the extracellular space and has been identified in the plasma of some individuals. HSP60 is thought to be a "danger signal" to the immune system and is also highly immunogenic. Thus extracellular HSP60 is possibly toxic to the cell. The mechanism by which HSP60 is released into the extracellular space is unknown, as is whether it is released by cardiac myocytes. We investigated several different pathways controlling protein release including the classic, Golgi-mediated pathway. We found that HSP60 is released via exosomes, and that within the exosome, HSP60 is tightly attached to the exosome membrane.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Amiloride / analogs & derivatives
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Amiloride / pharmacology
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Animals
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Brefeldin A / pharmacology
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Caveolin 1 / metabolism
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Cell Hypoxia
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Chaperonin 60 / metabolism*
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Golgi Apparatus / metabolism
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HSC70 Heat-Shock Proteins / metabolism
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HSP90 Heat-Shock Proteins / metabolism
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Male
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Membrane Microdomains / drug effects
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Membrane Microdomains / metabolism*
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Myocytes, Cardiac / drug effects
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Myocytes, Cardiac / metabolism*
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Protein Transport
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Rats
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Rats, Sprague-Dawley
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Secretory Vesicles / drug effects
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Secretory Vesicles / metabolism*
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Subcellular Fractions / metabolism
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beta-Cyclodextrins / pharmacology
Substances
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Caveolin 1
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Chaperonin 60
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HSC70 Heat-Shock Proteins
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HSP90 Heat-Shock Proteins
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Hspa8 protein, rat
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beta-Cyclodextrins
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methyl-beta-cyclodextrin
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Brefeldin A
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5-dimethylamiloride
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Amiloride