Dominant C‐terminal deletions of FtsZ that affect its ability to localize in Caulobacter and its interaction with FtsA

Abstract

SummaryThe cell division protein FtsZ is composed of three regions based on sequence similarity: a highly conserved N-terminal region of Ϸ320 amino acids; a variable spacer region; and a conserved C-terminal region of eight amino acids. We show that FtsZ mutants missing different C-terminal fragments have dominant lethal effects because they block cell division in Caulobacter crescentus by two different mechanisms. Removal of the C-terminal conserved region, the linker, and 40 amino acids from the end of the Nterminal conserved region (FtsZ⌬C281) prevents the localization or the polymerization of FtsZ. Because two-hybrid analysis indicates that FtsZ⌬C281 does not interact with FtsZ, we hypothesize that FtsZ⌬C281 blocks cell division by competing with a factor required for FtsZ localization or that it titrates a factor required for the stability of the FtsZ ring. The removal of 24 amino acids from the C-terminus of FtsZ (FtsZ⌬C485) causes a punctate pattern of FtsZ localization and affects its interaction with FtsA. This suggests that the conserved C-terminal region of FtsZ is required for proper polymerization of FtsZ in Caulobacter and for its interaction with FtsA.

Genetic Analysis of the Escherichia coli FtsZ·ZipA Interaction in the Yeast Two-hybrid System

“…The cell division machinery assembles on the Z-ring in a sequential manner. Two proteins that act early in cell division, and directly on the Z-ring, are FtsA and ZipA (5)(6)(7)(8)(9)(10). The structure of FtsA has been solved recently (11), and it supports previous indications that it is similar to actin (12,13).…”

“…4). The latter interaction was examined, because other work has suggested that FtsA also interacts with FtsZ at its C terminus, and we were therefore interested in characterizing this interaction (10,21,35). As can be seen in Fig.…”

“…Thus, it is a relatively simple extension of yeast genetic analysis to examine a twohybrid interaction genetically. Previous work has indicated that the C terminus of FtsZ is important for the interaction with both ZipA and FtsA (9,10,15,21,25). To better define the interaction between FtsZ and ZipA, we have analyzed this interaction in yeast genetically.…”

Role of the Carboxy Terminus of Escherichia coli FtsA in Self-Interaction and Cell Division

“…The yeast two-hybrid system (14) has already been used to detect interactions among some of the components of the bacterial cell division machinery, including those of the MinCDE system (20), and those of FtsZ with SulA (20), ZipA (25), SpoIIE (22), or FtsA (12,24,25,38,40). More recently, Yan et al (40) have reported the self-interaction of E. coli FtsA using the two-hybrid system, a result that has been confirmed in the present work.…”

“…The FtsZ/FtsA ratio is important for cell division, and the localization of FtsA to a central position along the cell length depends on the formation of the FtsZ ring (1,8,11,15,23). Accordingly, the interaction between FtsA and FtsZ from different bacteria has been established using the yeast two-hybrid system (12,25,38,40). In addition the presence of functional FtsA is required for the localization of FtsK, PBP3 (also known as FtsI), FtsQ, and FtsN to the septal ring (2,7,37,41), suggesting that FtsA may indeed be a part of a multiprotein complex (27).…”