Hsp21: Difference between revisions
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New page: == 'Structure of small heat shock protein (Hsp21)' == <Structure load='7BZW' size='400' frame='true' align='right' caption='Structure of small heat shock protein Hsp21' scene='Structure o... |
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== 'Structure of small heat shock protein (Hsp21)' == | == 'Structure of small heat shock protein (Hsp21)' == | ||
<Structure load='7BZW' size='400' frame='true' align='right' caption='Structure of small heat shock protein Hsp21' scene=' | <Structure load='7BZW' size='400' frame='true' align='right' caption='Structure of small heat shock protein Hsp21 (PDB code [[7bzw]])' scene='' /> | ||
== Introduction == | == Introduction == | ||
Small heat-shock proteins (sHSPs) constitute a highly conserved family of molecular chaperones that prevent stress-induced protein misfolding and aggregation, particularly during heat shock. Their expression can increase dramatically, reaching up to 1% of total cellular protein, highlighting their critical role in thermotolerance and in the regulation of cellular stress responses. sHSPs bind to denaturing proteins in an ATP-independent manner, thereby preventing irreversible aggregation. Rather than directly refolding substrate proteins, they act as a first line of defense by stabilizing unfolded or partially folded intermediates and subsequently coordinating with ATP-dependent chaperone systems, such as HSP70 and the HSP100/Clp chaperone machinery, to facilitate substrate disaggregation and refolding. | Small heat-shock proteins (sHSPs) constitute a highly conserved family of molecular chaperones that prevent stress-induced protein misfolding and aggregation, particularly during heat shock. Their expression can increase dramatically, reaching up to 1% of total cellular protein, highlighting their critical role in thermotolerance and in the regulation of cellular stress responses. sHSPs bind to denaturing proteins in an ATP-independent manner, thereby preventing irreversible aggregation. Rather than directly refolding substrate proteins, they act as a first line of defense by stabilizing unfolded or partially folded intermediates and subsequently coordinating with ATP-dependent chaperone systems, such as HSP70 and the HSP100/Clp chaperone machinery, to facilitate substrate disaggregation and refolding. | ||
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== Hsp21 == | == Hsp21 == | ||
Hsp21 is a chloroplast-localized small heat-shock protein present in all photosynthetic plants and has a crucial role in multiple developmental and stress-related processes, including chloroplast development, fruit ripening, thermomemory regulation, and protection of the photosynthetic apparatus during heat stress. | '''Hsp21''' is a chloroplast-localized small heat-shock protein present in all photosynthetic plants and has a crucial role in multiple developmental and stress-related processes, including chloroplast development, fruit ripening, thermomemory regulation, and protection of the photosynthetic apparatus during heat stress. | ||
== Structure of Hsp21 Revealed by Cryo-EM == | == Structure of Hsp21 Revealed by Cryo-EM == | ||
