[Molecular chaperones: new proteins--new functions].

A new class of cellular proteins named "molecular chaperones" has been described recently. Chaperones prevent from improper interactions either within or between polypeptide chains, which could produce incorrect structures. Chaperones assist in assembly or disassembly of oligomeric structures and in protein transport across membranes. There are three conservative families of chaperones and a few unrelated members. Some of them appeared to be stress proteins with yet unknown function. Mechanism of action and specificity of chaperone binding are under investigation now.