Induction of Hsp104 by Cr(VI) in yeast Candida intermedia | Indukcija Hsp104 S Cr(VI) pri kvasovki Candida intermedia

English. The synthesis of a polypeptide family named heat shock or stress proteins is one of the most conserved mechanisms of cellular protection in the case of changes in the environment. Among them Hsp104 is important, because it promotes survival of cells under extreme stresses such as high temperatures, severe oxidative damage and high concentrations of ethanol. The aim of our research was to investigate whether Hsp104 is induced in the yeast Candida intermedia exposed to Cr(VI). Namely, Cr(VI) belongs to redox active metals, which play an important role in the generation of reactive oxygen species in the cell and therefore they can lead to oxidative damages. Yeast cells were treated with Cr(VI) in the mid-exponential phase and after a defined time of incubation, Hsp104 induction was investigated by using Western blotting. Results showed that cultivation of yeast cells in the presence of 100 mM Cr(VI) caused induction of Hsp104, which is connected to formation of protein aggregates. Hsp104 assists their resolubilization and so contributes to cell survival. Its synthesis was detected 0.5 h after Cr(VI) addition and was later for up to 2 h more apparent. Therefore, we showed that Hsp104 plays an important role in the stress response of yeast Candida intermedia to Cr(VI).

Slovenian.  Sinteza družine polipeptidov, ki jih imenujemo proteini toplotnega šoka ali stresni proteini, je eden izmed  najbolj ohranjenih mehanizmov celične zaščite pri spremembah v okolju. Med njimi je pomemben Hsp104, ki omogoča preživetje celic v ekstremnih stresnih pogojih, kot so visoke temperature, močne oksidativne poškodbe in visoke koncentracije etanola. Namen naše raziskave je bil preučiti, če Cr(VI) povzroči indukcijo sinteze Hsp104 v kvasovki Candida intermedia. Cr(VI) namreč sodi med redoks aktivne kovine, ki imajo pomembno vlogo pri nastanku reaktivnih kisikovih zvrsti v celici in lahko vodijo do nastanka oksidativnih poškodb. Celice smo izpostavili Cr(VI) v sredini eksponentne faze rasti in po določenem času inkubacije preverjali indukcijo Hsp104 z analizo proteinov western. Rezultati so pokazali, da kultivacija celic v prisotnosti 100 µM koncentracije Cr(VI) povzroči indukcijo Hsp104, kar je povezano s tvorbo proteinskih agregatov. Hsp104 namreč pomaga raztopiti agregate in s tem celicam omogoči preživetje. Sinteza Hsp104 se je pojavila že 0,5 h po dodatku Cr(VI), kasneje tja do dveh ur pa se je še povečala. V raziskavi smo pokazali, da ima Hsp104 pomembno vlogo v stresnem odgovoru kvasovke na Cr(VI).