Dash-and-Recruit Mechanism Drives Membrane Curvature Recognition by the Small Bacterial Protein SpoVM

作者：Kim Edward Y; Tyndall Erin R; Huang Kerwyn Casey^*; Tian Fang^*; Ramamurthi Kumaran S^*

来源：Cell Systems, 2017, 5(5): 518-+.

DOI：10.1016/j.cels.2017.10.004

In Bacillus subtilis, sporulation requires that the 26-amino acid protein SpoVM embeds specifically into the forespore membrane, a structure with convex curvature. How this nanometer-sized protein can detect curves on a micrometer scale is not well understood. Here, we report that SpoVM exploits a "dash-and-recruit'' mechanism to preferentially accumulate on the forespore. Using time-resolved imaging and flow cytometry, we observe that SpoVM exhibits a faster adsorption rate onto membranes of higher convex curvature. This preferential adsorption is accurately modeled as a two-step process: first, an initial binding event occurs with a faster on rate, then cooperative recruitment of additional SpoVM molecules follows. We demonstrate that both this biochemical process and effective sporulation in vivo require an unstructured and flexible SpoVM N terminus. We propose that this two-pronged strategy of fast adsorption followed by recruitment of subsequent molecules is a general mechanism that allows small proteins to detect subtle curves with a radius 1,000-fold their size.

• 出版日期2017-11-22
• 单位NIH