Chen J, Zhou S, Wang Q, Chen X, Pan T, Liu H
State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry, Chinese Academy of Sciences, Shanghai 200031, China.
Mol Cell Biol. 2000 Dec;20(23):8696-708. doi: 10.1128/MCB.20.23.8696-8708.2000.
Both mitogen-activated protein kinases and cyclin-dependent kinases play a role in hyphal development in Candida albicans. Using an oligonucleotide probe-based screen, we have isolated a new member of the Cdc2 kinase subfamily, designated Crk1 (Cdc2-related kinase). The protein sequence of Crk1 is most similar to those of Saccharomyces cerevisiae Sgv1 and human Pkl1/Cdk9. In S. cerevisiae, CRK1 suppresses some, but not all, of the defects associated with an sgv1 mutant. Deleting both copies of CRK1 in C. albicans slows growth slightly but leads to a profound defect in hyphal development under all conditions examined. crk1/crk1 mutants are impaired in the induction of hypha-specific genes and are avirulent in mice. Consistent with this, ectopic expression of the Crk1 kinase domain (CRK1N) promotes filamentous or invasive growth in S. cerevisiae and hyphal development in C. albicans. The activity of Crk1 in S. cerevisiae requires Flo8 but is independent of Ste12 and Phd1. Similarly, Crk1 promotes filamentation through a route independent of Cph1 and Efg1 in C. albicans. RAS1(V13) can also activate filamentation in a cph1/cph1 efg1/efg1 double mutant. Interestingly, CRK1N produces florid hyphae in ras1/ras1 strains, while RAS1(V13) generates feeble hyphae in crk1/crk1 strains.
丝裂原活化蛋白激酶和细胞周期蛋白依赖性激酶在白色念珠菌的菌丝发育中均发挥作用。通过基于寡核苷酸探针的筛选，我们分离出了Cdc2激酶亚家族的一个新成员，命名为Crk1（Cdc2相关激酶）。Crk1的蛋白质序列与酿酒酵母的Sgv1和人类的Pkl1/Cdk9最为相似。在酿酒酵母中，CRK1可抑制与sgv1突变体相关的部分而非全部缺陷。在白色念珠菌中删除CRK1的两个拷贝会使生长略有减缓，但在所有检测条件下均导致菌丝发育出现严重缺陷。crk1/crk1突变体在菌丝特异性基因的诱导方面存在缺陷，并且在小鼠中无致病性。与此一致的是，Crk1激酶结构域（CRK1N）的异位表达促进了酿酒酵母中的丝状或侵袭性生长以及白色念珠菌中的菌丝发育。Crk1在酿酒酵母中的活性需要Flo8，但不依赖于Ste12和Phd1。同样，在白色念珠菌中，Crk1通过一条不依赖于Cph1和Efg1的途径促进菌丝形成。RAS1(V13)也可在cph1/cph1 efg1/efg1双突变体中激活菌丝形成。有趣的是，CRK1N在ras1/ras1菌株中产生繁茂的菌丝，而RAS1(V13)在crk1/crk1菌株中产生微弱的菌丝。
