The MAP kinase-activated protein kinase Rck2p plays a role in rapamycin sensitivity inSaccharomyces cerevisiaeandCandida albicans

Abstract

Rck2p is a Hog1p-MAP kinase-activated protein kinase and regulates osmotic and oxidative stresses in budding yeast. In this study, we have demonstrated in both Saccharomyces cerevisiae and, the most medically important human fungal pathogen, Candida albicans that deletion of RCK2 renders cells sensitive to rapamycin, the inhibitor of target of rapamycin protein kinase controlling cell growth. The kinase activity of Rck2p does not seem to be required for this rapamycin sensitivity function in both eukaryotic microorganisms. Interestingly, the HOG pathway is not directly involved in cell sensitivity to rapamycin in S. cerevisiae, whereas disruption of CaHOG1 renders cells sensitive to rapamycin in C. albicans. In addition, we have shown that CaRck2p and its kinase activity are required for cell growth in C. albicans.

The protein kinase CaSch9p is required for the cell growth, filamentation and virulence in the human fungal pathogen Candida albicans

“…We replaced the two alleles of CaSCH9 with the disruption cassette constructed in the plasmid p5921 containing a hisG ‐ URA3 ‐ hisG as the selectable and recyclable maker (Supporting Information, Fig. S1; Fonzi & Irwin, 1993; Li et al ., 2008). First, an 849‐bp DNA fragment upstream of the start codon of CaSCH9 was amplified with primers CaSCH9a‐F and CaSCH9a‐R (5′‐GAAGATCTCC CGTCCTCAAT TCCGTTC‐3′, BglII site underlined), and this fragment was digested with KpnI and BglII to be cloned into the KpnI and BglII sites at one side of the hisG ‐ URA3 ‐ hisG cassette in p5921, yielding p5921‐CaSCH9a.…”

Genetic interactions between protein phosphatases CaPtc2p and CaPph3p in response to genotoxins and rapamycin inCandida albicans

“…The CaPPH3 fragment was excised from the pMD18-CaPPH3 and subcloned into the SacI and HindIII sites of pCR4 (Li et al, 2008), which yielded pCR4-CaPPH3. The CaPPH3 fragment was excised from the pMD18-CaPPH3 and subcloned into the SacI and HindIII sites of pCR4 (Li et al, 2008), which yielded pCR4-CaPPH3.…”

The MAP kinase-activated protein kinase Rck2p regulates cellular responses to cell wall stresses, filamentation and virulence in the human fungal pathogen Candida albicans

“…Candida albicans strain RM1000 ( ura3 Δ∷ imm434 / ura3 Δ∷ imm434 his1 ∷ hisG / his1 ∷ hisG ) was used in previous studies (Negredo et al , 1997; Wang et al , 2007; Zheng et al , 2007). The heterozygous mutant BH2 (RM1000 RCK2 / rck2 ∷ hisG ) and homozygous mutant BH4 (RM1000 rck2 ∷ hisG / rck2 ∷ hisG ) were generated in our previous study (Li et al , 2008). For nonselective conditions, the medium was YPD (1% yeast extract, 2% peptone, 2% glucose).…”

“…To express the ScRCK2 gene in C. albicans cells, the wild‐type ScRCK2 and the KD ScRCK2KD mutant alleles were cloned in the C. albicans expression vector pCR4 in our previous study, which yielded pCR4‐ScRCK2 and pCR4‐ScRCK2KD (Li et al , 2008).…”

“…Microarray analyses have revealed that transcripts for ribosomal proteins and proteins involved in the processing and assembly of ribosomes are deregulated in cells deleted of ScRCK2 (Swaminathan et al , 2006). Consistently, Rck2p is involved in the sensitivity to rapamycin, the inhibitor of TORC1, in both S. cerevisiae and Candida albicans (Li et al , 2008).…”