THE EFFECT OF ANNEALING AND ILLUMINATION ON THE FIELD EFFECT CONDUCTANCE OF AMORPHOUS SILICON

We have measured the effect of white light illumination and annealing to 180°C on the field effect conductance of glow discharge α-Si : H. Annealing produces a change in the off conductance by up to a factor of 30, and moves the threshold field by 2 x 104 Vcm-1. These changes are reproducibly reversed upon illuminating with white light. A major part of the effect of illumination is most likely due to a movement of the Fermi level in the bulk of the material. Annealing to 180°C reverses this effect. Furthermore excess electrons can be trapped at the amorphous silicon-silicon nitride interface by a field assisted trapping mechanism and these are also de-trapped upon annealing to 180°C

Overexpression of Yeast Hsp110 Homolog Sse1p Suppresses ydj1-151 Thermosensitivity and Restores Hsp90-dependent Activity

The Saccharomyces cerevisiae heat-shock protein (Hsp)40, Ydj1p, is involved in a variety of cellular activities that control polypeptide fate, such as folding and translocation across intracellular membranes. To elucidate the mechanism of Ydj1p action, and to identify functional partners, we screened for multicopy suppressors of the temperature-sensitive ydj1-151 mutant and identified a yeast Hsp110, SSE1. Overexpression of Sse1p also suppressed the folding defect of v-Src kinase in the ydj1-151 mutant and partially reversed the α-factor translocation defect. SSE1-dependent suppression of ydj1-151 thermosensitivity required the wild-type ATP-binding domain of Sse1p. However, the Sse1p mutants maintained heat-denatured firefly luciferase in a folding-competent state in vitro and restored human androgen receptor folding in sse1 mutant cells. Because the folding of both v-Src kinase and human androgen receptor in yeast requires the Hsp90 complex, these data suggest that Ydj1p and Sse1p are interacting cochaperones in the Hsp90 complex and facilitate Hsp90-dependent activity