C. elegans STI-1, the homolog of Sti1/Hop, is involved in aging and stress response.
Environmental and physiological stresses such as heat shock, oxidative stress, heavy metals, and pathogenic conditions induce cellular stress response. This response is often mediated by heat shock proteins that function as molecular chaperones. A stress-inducible cochaperone, Sti1/Hop (Hsp organizer protein), functions as an adaptor protein that simultaneously binds with Hsp70 and Hsp90 to transfer client proteins from Hsp70 to Hsp90. However, the biological role of STI-1 in vivo is poorly understood in metazoans. Here, we report the characterization of the Caenorhabditis elegans homolog of Sti1/Hop, which is approximately 56% identical with human STI-1. C. elegans STI-1 (CeSTI-1) is expressed in the pharynx, intestine, nervous system, and muscle from larvae to adults. Analysis of proteins immunoprecipitated with anti-STI-1 antibody by mass spectrometry revealed that CeSTI-1 can bind with both Hsp70 and Hsp90 homologs like its mammalian counterpart. sti-1 expression is elevated by heat stress, and an sti-1(jh125) null mutant shows decreased fertility under heat stress conditions. These mutants also show abnormally high lethality in extreme heat and may be functioning with DAF-16 in thermotolerance. In addition, sti-1(jh125) mutants have a shortened life span. Our results confirm that CeSTI-1 is a cochaperone protein that may maintain homeostatic functions during episodes of stress and can regulate longevity in nematodes.
Song
Hyun-Ok
HO
Department of Life Science, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea.
Lee
Wonhae
W
An
Kiyoung
K
Lee
Hye-suk
HS
Cho
Jeong Hoon
JH
Park
Zee-Yong
ZY
Ahnn
Joohong
J
D000375:Aging / Q000502:physiology; D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000254:growth & development / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000502:physiology*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000502:physiology*; D018869:Heat-Shock Response; D006358:Hot Temperature; D006801:Humans; D007814:Larva / Q000378:metabolism; D008136:Longevity / Q000502:physiology; D018832:Molecular Chaperones / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D013312:Stress, Physiological
D029742:Caenorhabditis elegans Proteins; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; C543375:STI-1 protein, C elegans; C079373:STIP1 protein, human