Uncovering Principles That Control Septin-Septin Interactions

作者：Kim Moshe S; Froese Carol D; Xie Hong; Trimble William S^*

来源：JOURNAL OF BIOLOGICAL CHEMISTRY, 2012, 287(36): 30406-30413.

DOI：10.1074/jbc.M112.387464

Septins comprise a conserved family of GTPases important in cytokinesis. These proteins polymerize into filaments from rod-shaped heteromeric septin complexes. Septins interact with one another at two interfaces (NC and G) that alternate within the complex. Here, we show that small mutations at the N terminus greatly enhance the formation of SEPT2 homopolymers. Taking advantage of this mutation to examine polymer formation using SEPT2 alone, we show that both NC and G interfaces are required for filament formation. However, co-expression of wild type SEPT2 with SEPT2 containing mutations at either NC or G interfaces revealed that only the NC mutant suppressed filament formation. NC mutants are able to interact with one another at putative Ginterfaces, whereas G mutants fail to interact at NC interfaces. In addition, all promiscuous septin pair-wise interactions occur at the G interface. These findings suggest that G interface interactions must occur before NC interactions during polymer formation.

• 出版日期2012-8-31