[Protein folding with molecular chaperones:stochastic process under control]. 
Protein folding in a living cell occurs with the participation of specialized proteins, molecular shaperons.  The functional role and molecular mechanism of action of shaperons are discussed.  It is shown that shaperons can be considered as proteins that, upon interaction with the folding peptide chain, transform the spontaneous folding to a process controlled and regulated by cellular factors.  Models describing these controlled phenomena are discussed.