Regulation of the extracellular matrix by heat shock proteins and molecular chaperones:

The extracellular matrix (ECM) serves as a scaffold for cells within tissues and is composed of an intricate network of glycoproteins, growth factors and matricellular proteins which cooperatively function in cell processes such as migration, adhesion and wound healing. ECM morphology is constantly undergoing remodelling (synthesis, assembly and degradation) during normal cell processes and when deregulated may contribute to disease. Heat shock proteins (Hsps) are involved in regulating processes that determine the assembly and degradation of the ECM at multiple levels, in both normal and diseased states. These roles include mediating the activation of ECM-degrading enzymes, maintaining matrix stability and clearing aggregated/misfolded proteins. Hsp may serve as chaperones and receptors or have cytokine-like functions. In this chapter, we review how Hsp90, Hsp70, Hsp40 and a number of ER resident chaperones contribute to ECM regulation. The role of the non-Hsp chaperones, SPARC and clusterin in the ECM is also discussed