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1.E.14 The LrgA Holin (LrgA Holin) Family

See 1.E for a generalized description of Holins.


LrgA is a 145 aa protein with 4 putative TMSs. It is a member of a large family of putative murine hydrolase exporters from a wide range of Gram-positive and Gram-negative bacteria as well as archaea. Most vary in size between 100 and 160 aas although a few are larger. It has been proposed that together with their homologues, CidAB (23% and 32% identical to LrgAB, respectively) are involved in programmed cell death in a process that is analogous to apoptosis in eukaryotes (Bayles, 2003). CidA, a 131 aa protein with 4 putative TMSs, is believed to be the holin which exports the autolysin CidB, while LrgA may be an antiholin. If this is a general mechanism for programmed cell death, this would explain their near ubiquity in the prokaryotic world. The cidABC operon is activated by CidR in the presence of acetic acid (Yang et al., 2005).  LrgAB affect biofilm formation and oxidative stress and may be linked to competence in S. mutants (Ahn et al. 2012).



References associated with 1.E.14 family:

Ahn, S.J., M.D. Qu, E. Roberts, R.A. Burne, and K.C. Rice. (2012). Identification of the Streptococcus mutans LytST two-component regulon reveals its contribution to oxidative stress tolerance. BMC Microbiol 12: 187. 22937869
Bayles, K.W. (2003). Are the molecular strategies that control apoptosis conserved in bacteria? Trends Microbiol. 11: 306-311. 12875813
Brunskill, E.W. and K.W. Bayles. (1996). Identification of LytSR-regulated genes from Staphylococcus aureus. J. Bacteriol. 178: 5810-5812. 8824633
Fischer, A., K. Kambara, H. Meyer, L. Stenz, E.J. Bonetti, M. Girard, M. Lalk, P. Francois, and J. Schrenzel. (2013). GdpS contributes to Staphylococcus aureus biofilm formation by regulation of eDNA release. Int. J. Med. Microbiol. [Epub: Ahead of Print] 24275081
Patton, T.G., K.C. Rice, M.K. Foster, and K.W. Bayles. (2005). The Staphylococcus aureus cidC gene encodes a pyruvate oxidase that affects acetate metabolism and cell death in stationary phase. Mol. Microbiol. 56: 1664-1674. 15916614
Ranjit, D.K., J.L. Endres, and K.W. Bayles. (2011). Staphylococcus aureus CidA and LrgA proteins exhibit holin-like properties. J. Bacteriol. 193: 2468-2476. 21421752
Yang, S.J., K.C. Rice, R.J. Brown, T.G. Patton, L.E. Liou, Y.H. Park, and K.W. Bayles. (2005). A LysR-type regulator, CidR, is required for induction of the Staphylococcus aureus cidABC operon. J. Bacteriol. 187: 5893-5900. 16109930