Structure and mechanism of Candida albicans Int1 involved in septin organization regulation / 中华微生物学和免疫学杂志

ABSTRACT

Objective:To investigate the mechanism of Candida albicans Int1 in regulating septin organization. Methods:A series of full-length and truncated fragments of Int1 were constructed and fused with green fluorescent protein (GFP). The intracellular localization of the fusion proteins was observed under a fluorescence microscope. The region in Int1 that was required for bud neck localization was identified. Full-length and fragments of Int1 were overexpressed in the yeast Saccharomyces cerevisiae and the changes in cell growth, cell morphology and septin organization were investigated to determine the functional region in Int1 that mediated the interaction with septin. Moreover, the co-localization of the region and septin was analyzed. Results:The full-length Int1 consisted of 1 661 amino acid residues. A middle region of 209 amino acid residues, Int1-M4 (739-947 aa), that could be localized at the bud neck during both small and large bud periods was identified. Overexpression of Int1-M4 led to significant growth defects, elongated bud and disorganized septin. In the cells with elongated bud, Int1-M4 and septin with abnormal structures could be co-localized.Conclusions:Int1-M4 (739-947 aa), the middle region of Int1 containing 209 amino acid residues, mediated the bud neck localization and the interaction with septin, playing an important role in regulating septin organization.