A multidomain hub anchors the chromosome segregation and chemotactic machinery to the bacterial pole

Division of Infectious Diseases, Brigham and Women's Hospital.
Genes & development (Impact Factor: 10.8). 10/2012; 26(20):2348-60. DOI: 10.1101/gad.199869.112
Source: PubMed


The cell poles constitute key subcellular domains that are often critical for motility, chemotaxis, and chromosome segregation in rod-shaped bacteria. However, in nearly all rods, the processes that underlie the formation, recognition, and perpetuation of the polar domains are largely unknown. Here, in Vibrio cholerae, we identified HubP (hub of the pole), a polar transmembrane protein conserved in all vibrios, that anchors three ParA-like ATPases to the cell poles and, through them, controls polar localization of the chromosome origin, the chemotactic machinery, and the flagellum. In the absence of HubP, oriCI is not targeted to the cell poles, chemotaxis is impaired, and a small but increased fraction of cells produces multiple, rather than single, flagella. Distinct cytoplasmic domains within HubP are required for polar targeting of the three ATPases, while a periplasmic portion of HubP is required for its localization. HubP partially relocalizes from the poles to the mid-cell prior to cell division, thereby enabling perpetuation of the polar domain in future daughter cells. Thus, a single polar hub is instrumental for establishing polar identity and organization.

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    • "asmussen et al . , 2007 ) . Moreover , the chromosomal position of genes determines the relative copy number during growth thereby impacting the bacteriums physiology ( Soler - Bistue et al . , 2015 ) . Notably , mechanistic aspects of chromosome organization , architecture , and cell cycle - dependent dynamics are only starting to be deciphered ( Yamaichi et al . , 2012 ; Demarre et al . , 2014 ) . The elucidation of the mechanisms that coordinate the interplay between chromosomes , accessory replicons , mobile DNA and HGT mechanisms is essential to better apprehend the evolution and niche adaptation of Vibrio species ."
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    • "Many studies on Par homologues (plasmid and chromosomally encoded) have demonstrated a role for a dynamic ParA scaffold and the importance of ParA–ParB interactions in bacterial DNA segregation (reviewed by Gerdes et al., 2010; Banigan et al., 2011; Hwang et al., 2013; Lim et al., 2014; Scholefield et al., 2011; Vecchiarelli et al., 2013). In the case of chromosomally encoded Par proteins, their roles in regulation of other cellular processes in a species-specific manner were also demonstrated (Kadoya et al., 2011; Murray & Errington, 2008; Scholefield et al., 2011; Thanbichler & Shapiro, 2006; Yamaichi et al., 2012). Whilst the ParB homologues have been dissected with respect to DNA binding, and dimerization/oligomerization domains, and in many cases the domains of interactions with the ParA homologues identified (Ah-Seng et al., 2009; Barillà et al., 2007; Bartosik et al., 2004; Figge et al., 2003; Kim & Shim, 1999; Leonard et al., 2004; Lukaszewicz et al., 2002; Scholefield et al., 2011; Surtees & Funnell, 1999), less is known about regions of ParA homologues involved in reciprocal interactions with the cognate partners (Jakimowicz et al., 2007; Leonard et al., 2005; Ravin et al., 2003; Scholefield et al., 2011). "
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    • "Polarly localized HubP interacts directly with the ParA1 ATPase, which is involved in segregation of chromosome 1 (Fogel and Waldor, 2006), and the ParA ATPase FlhG, which regulates flagellar assembly together with the GTPase FlhF (Fig. 3 C; Correa et al., 2005; Yamaichi et al., 2012). HubP also recruits—but does not directly interact with—the ParA ATPase ParC, which is required for the polar recruitment of chemotaxis proteins (Fig. 3 C; Ringgaard et al., 2011; Yamaichi et al., 2012). ParC, in turn, recruits the ParP protein to the pole by direct interaction , and ParP as well as ParC interact with the CheA kinase , in that way stimulating the formation of a large complex of chemotaxis proteins at the pole (Ringgaard et al., 2014). "
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