In vitro evidence of Hsc70 functioning as a molecular chaperone during cold stress

• Published in: Plant physiology and biochemistry 2006-11, Vol.44 (11), p.844-850
• Main Authors: Zhang, C., Guy, C.L.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Cold stress; Cold Temperature; Fundamental and applied biological sciences. Psychology; HSC70 Heat-Shock Proteins - chemistry; HSC70 Heat-Shock Proteins - genetics; HSC70 Heat-Shock Proteins - metabolism; Hsc70s; Hsp70s; Low temperature; Physical agents; Plant physiology and development; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Protein Binding; Protein Folding; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Spinach; Spinacia oleracea; Spinacia oleracea - chemistry; Spinacia oleracea - genetics; Spinacia oleracea - metabolism; Substrate binding; Unfolded proteins; Vegetative apparatus, growth and morphogenesis. Senescence
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2006.09.012

Hsp70 molecular chaperones have been shown to play an important role in helping cells to cope with adverse environments, especially in response to high temperatures. The molecular chaperone function of Hsc70 at low temperature was investigated. A cold-inducible spinach cytosolic Hsc70 was subcloned into a protein expression vector and the recombinant protein was expressed in bacterial cells. Recombinant Hsc70 bound a permanently unfolded substrate: α-carboxymethylated lactalbumin (CMLA) in the presence of 3 mM ATP and MgCl 2 at low temperature (4 and –4 °C). Radiolabeling with 35S-Met and 35S-Cys and immunoprecipitation with cytosolic Hsc70 monoclonal antibodies showed that there were several proteins co-immunoprecipitated at low temperature (4 and –4 °C) but not at room temperature. Enhanced co-purification of sHsp17.7 with Hsc70 at low temperature was observed and suggests that co-chaperone interactions can contribute to molecular chaperone function during cold stress. These results suggest that the molecular chaperone Hsc70 may have a functional role in plants during low temperature stress.