a Department of Biotechnology , College of Life Science and Biotechnology, Yonsei University , Seoul , Republic of Korea.
b Research Division for Biotechnology, Korea Atomic Energy Research Institute , Jeongeup , Republic of Korea.
Virulence. 2018 Jan 1;9(1):566-584. doi: 10.1080/21505594.2017.1423189.
Microtubules are involved in mechanical support, cytoplasmic organization, and several cellular processes by interacting with diverse microtubule-associated proteins such as plus-end tracking proteins, motor proteins, and tubulin-folding cofactors. A number of the cytoskeleton-associated proteins (CAPs) contain the CAP-glycine-rich (CAP-Gly) domain, which is evolutionarily conserved and generally considered to bind to α-tubulin to regulate the function of microtubules. However, there has been a dearth of research on CAP-Gly proteins in fungal pathogens, including Cryptococcus neoformans, which is a global cause of fatal meningoencephalitis in immunocompromised patients. In this study, we identified five CAP-Gly protein-encoding genes in C. neoformans. Among these, Cgp1 encoded by CNAG_06352 has a unique domain structure containing CAP-Gly, SPEC, and Spc7 domains that is not orthologous to CAPs in other eukaryotes. Supporting the role of Cgp1 in microtubule-related function, we demonstrate that deletion or overexpression of CGP1 alters cellular susceptibility to thiabendazole, a microtubule destabilizer and that Cgp1 is co-localized with cytoplasmic microtubules. Related to the cellular function of microtubules, Cgp1 governs the maintenance of membrane stability and genotoxic stress responses. Deletion of CGP1 also reduces production of melanin pigment and attenuates the virulence of C. neoformans. Furthermore, we demonstrate that Cgp1 uniquely regulates the sexual differentiation of C. neoformans with distinct roles in the early and late stage of mating. Domain analysis revealed that the CAP-Gly domain plays a major role in all Cgp1 functions examined. In conclusion, this novel CAP-Gly protein, Cgp1, has pleotropic roles in regulating growth, stress responses, differentiation, and virulence in C. neoformans.
微管通过与各种微管相关蛋白（如末端追踪蛋白、马达蛋白和微管折叠辅助因子）相互作用，参与机械支持、细胞质组织和几种细胞过程。许多细胞骨架相关蛋白（CAPs）含有 CAP-甘氨酸丰富（CAP-Gly）结构域，该结构域在进化上是保守的，通常被认为与α-微管结合，以调节微管的功能。然而，真菌病原体（包括新生隐球菌）中 CAP-Gly 蛋白的研究相对较少，新生隐球菌是免疫功能低下患者致命性脑膜脑炎的全球病因。在这项研究中，我们在新生隐球菌中鉴定了五个 CAP-Gly 蛋白编码基因。其中，由 CNAG_06352 编码的 Cgp1 具有独特的结构域结构，包含 CAP-Gly、SPEC 和 Spc7 结构域，与其他真核生物中的 CAP 没有同源性。支持 Cgp1 在微管相关功能中的作用，我们证明 CGP1 的缺失或过表达会改变细胞对噻苯达唑（一种微管稳定剂）的敏感性，并且 Cgp1 与细胞质微管共定位。与微管的细胞功能有关，Cgp1 控制膜稳定性和遗传毒性应激反应的维持。CGP1 的缺失也会减少黑色素的产生，并降低新生隐球菌的毒力。此外，我们证明 Cgp1 独特地调节新生隐球菌的有性分化，在交配的早期和晚期阶段具有不同的作用。结构域分析表明，CAP-Gly 结构域在所有 Cgp1 功能中起主要作用。总之，这种新型 CAP-Gly 蛋白 Cgp1 在调节新生隐球菌的生长、应激反应、分化和毒力方面具有多种作用。
