HSP27 Human

Heat Shock Protein 27 (HSP27), also known as Heat Shock Protein Beta-1 (HSPB1), is a small heat shock protein (sHSP) that plays a crucial role in cellular stress response. It is a molecular chaperone involved in protein folding, inhibition of apoptosis, and regulation of the cytoskeleton. HSP27 is encoded by the HSPB1 gene in humans .

HSP27 belongs to the small heat shock protein family, characterized by a conserved α-crystallin domain. This domain is essential for the protein’s chaperone activity, allowing it to prevent the aggregation of unfolded proteins . The protein exists in both unphosphorylated inactive and phosphorylated active forms .

HSP27 forms large oligomers, which are essential for its function. These oligomers consist of stable dimers formed by the α-crystallin domains of neighboring monomers . The N-terminal region of HSP27 is crucial for the development of these oligomers .

HSP27 is upregulated in response to various stress conditions, including heat shock, oxidative stress, and chemical stress . It functions as an antioxidant by lowering reactive oxygen species (ROS) levels and increasing intracellular glutathione levels . Additionally, HSP27 inhibits apoptosis by interacting with both mitochondrial-dependent and independent pathways .

HSP27 has been implicated in various disease states, including renal injury, fibrosis, cancer, neurodegenerative diseases, and cardiovascular diseases . Its role as a protein chaperone and antioxidant makes it a potential therapeutic target. HSP27’s anti-apoptotic properties have significant implications for the success of certain chemotherapies .

Recent studies have shown that HSP27 is not only an intracellular chaperone but also exists in the extracellular space. In the extracellular environment, HSP27 can signal via membrane receptors to alter gene transcription and cellular function .