Small Heat Shock Proteins and Distal Hereditary Neuropathies

Classification of small heat shock proteins (sHsp) is presented and processes regulated by sHsp are described. Symptoms of hereditary distal neuropathy are described and the genes whose mutations are associated with development of this congenital disease are listed. The literature data and our own results concerning physicochemical properties of HspB1 mutants associated with Charcot-Marie-Tooth disease are analyzed. Mutations of HspB1, associated with hereditary motor neuron disease, can be accompanied by change of the size of HspB1 oligomers, by decreased stability under unfavorable conditions, by changes in the interaction with protein partners, and as a rule by decrease of chaperone-like activity. The largest part of these mutations is accompanied by change of oligomer stability (that can be either increased or decreased) or by change of intermonomer interaction inside an oligomer. Data on point mutation of HspB3 associated with axonal neuropathy are presented. Data concerning point mutations of Lys141 of HspB8 and those associated with hereditary neuropathy and different forms of Charcot-Marie-Tooth disease are analyzed. It is supposed that point mutations of sHsp associated with distal neuropathies lead either to loss of function (for instance, decrease of chaperone-like activity) or to gain of harmful functions (for instance, increase of interaction with certain protein partners).