| Structural highlights
Function
[SP3AH_BACSU] Involved in forespore engulfment. Forms a channel with SpoIIIAH that is open on the forespore end and closed (or gated) on the mother cell end. This allows sigma-E-directed gene expression in the mother-cell compartment of the sporangium to trigger the activation of sigma-G forespore-specific gene expression by a pathway of intercellular signaling.[1] [2] [3] [4] [5] [6] [7] [SP2Q_BACSU] Involved in forespore engulfment and required for anchoring membrane proteins on the forespore side of the septal membrane. Forms a channel with SpoIIIAH that is open on the forespore end and closed (or gated) on the mother cell end. This allows sigma-E-directed gene expression in the mother-cell compartment of the sporangium to trigger the activation of sigma-G forespore-specific gene expression by a pathway of intercellular signaling.[8] [9] [10] [11] [12] [13] [14] [15] [16] [17]
Publication Abstract from PubMed
Proteins SpoIIQ and SpoIIIAH interact through two membranes to connect the forespore and the mother cell during endospore development in the bacterium Bacillus subtilis. SpoIIIAH consists of a transmembrane segment and an extracellular domain with similarity to YscJ proteins. YscJ proteins form large multimeric rings that are the structural scaffolds for the assembly of type III secretion systems in Gram-negative bacteria. The predicted ring-forming motif of SpoIIIAH and other evidence led to the model that SpoIIQ and SpoIIIAH form the core components of a channel or transporter through which the mother cell nurtures forespore development. Therefore, to understand the roles of SpoIIIAH and SpoIIQ in channel formation, it is critical to determine whether SpoIIIAH adopts a ring-forming structural motif, and whether interaction of SpoIIIAH with SpoIIQ would preclude ring formation. We report a 2.8-A resolution structure of a complex of SpoIIQ and SpoIIIAH. SpoIIIAH folds into the ring-building structural motif, and modeling shows that the structure of the SpoIIQ-SpoIIIAH complex is compatible with forming a symmetrical oligomer that is similar to those in type III systems. The inner diameters of the two most likely ring models are large enough to accommodate several copies of other integral membrane proteins. SpoIIQ contains a LytM domain, which is found in metalloendopeptidases, but lacks residues important for metalloprotease activity. Other LytM domains appear to be involved in protein-protein interactions. We found that the LytM domain of SpoIIQ contains an accessory region that interacts with SpoIIIAH.
Structure of the basal components of a bacterial transporter.,Meisner J, Maehigashi T, Andre I, Dunham CM, Moran CP Jr Proc Natl Acad Sci U S A. 2012 Apr 3;109(14):5446-51. Epub 2012 Mar 19. PMID:22431613[18]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Blaylock B, Jiang X, Rubio A, Moran CP Jr, Pogliano K. Zipper-like interaction between proteins in adjacent daughter cells mediates protein localization. Genes Dev. 2004 Dec 1;18(23):2916-28. PMID:15574594 doi:http://dx.doi.org/10.1101/gad.1252704
- ↑ Doan T, Marquis KA, Rudner DZ. Subcellular localization of a sporulation membrane protein is achieved through a network of interactions along and across the septum. Mol Microbiol. 2005 Mar;55(6):1767-81. PMID:15752199 doi:http://dx.doi.org/10.1111/j.1365-2958.2005.04501.x
- ↑ Jiang X, Rubio A, Chiba S, Pogliano K. Engulfment-regulated proteolysis of SpoIIQ: evidence that dual checkpoints control sigma activity. Mol Microbiol. 2005 Oct;58(1):102-15. PMID:16164552 doi:http://dx.doi.org/MMI4811
- ↑ Broder DH, Pogliano K. Forespore engulfment mediated by a ratchet-like mechanism. Cell. 2006 Sep 8;126(5):917-28. PMID:16959571 doi:http://dx.doi.org/10.1016/j.cell.2006.06.053
- ↑ Aung S, Shum J, Abanes-De Mello A, Broder DH, Fredlund-Gutierrez J, Chiba S, Pogliano K. Dual localization pathways for the engulfment proteins during Bacillus subtilis sporulation. Mol Microbiol. 2007 Sep;65(6):1534-46. PMID:17824930 doi:http://dx.doi.org/MMI5887
- ↑ Camp AH, Losick R. A novel pathway of intercellular signalling in Bacillus subtilis involves a protein with similarity to a component of type III secretion channels. Mol Microbiol. 2008 Jul;69(2):402-17. doi: 10.1111/j.1365-2958.2008.06289.x. PMID:18485064 doi:http://dx.doi.org/10.1111/j.1365-2958.2008.06289.x
- ↑ Meisner J, Wang X, Serrano M, Henriques AO, Moran CP Jr. A channel connecting the mother cell and forespore during bacterial endospore formation. Proc Natl Acad Sci U S A. 2008 Sep 30;105(39):15100-5. doi:, 10.1073/pnas.0806301105. Epub 2008 Sep 23. PMID:18812514 doi:http://dx.doi.org/10.1073/pnas.0806301105
- ↑ Londono-Vallejo JA, Frehel C, Stragier P. SpoIIQ, a forespore-expressed gene required for engulfment in Bacillus subtilis. Mol Microbiol. 1997 Apr;24(1):29-39. PMID:9140963
- ↑ Sun YL, Sharp MD, Pogliano K. A dispensable role for forespore-specific gene expression in engulfment of the forespore during sporulation of Bacillus subtilis. J Bacteriol. 2000 May;182(10):2919-27. PMID:10781563
- ↑ Dworkin J, Losick R. Developmental commitment in a bacterium. Cell. 2005 May 6;121(3):401-9. PMID:15882622 doi:http://dx.doi.org/10.1016/j.cell.2005.02.032
- ↑ Doan T, Marquis KA, Rudner DZ. Subcellular localization of a sporulation membrane protein is achieved through a network of interactions along and across the septum. Mol Microbiol. 2005 Mar;55(6):1767-81. PMID:15752199 doi:http://dx.doi.org/10.1111/j.1365-2958.2005.04501.x
- ↑ Jiang X, Rubio A, Chiba S, Pogliano K. Engulfment-regulated proteolysis of SpoIIQ: evidence that dual checkpoints control sigma activity. Mol Microbiol. 2005 Oct;58(1):102-15. PMID:16164552 doi:http://dx.doi.org/MMI4811
- ↑ Broder DH, Pogliano K. Forespore engulfment mediated by a ratchet-like mechanism. Cell. 2006 Sep 8;126(5):917-28. PMID:16959571 doi:http://dx.doi.org/10.1016/j.cell.2006.06.053
- ↑ Aung S, Shum J, Abanes-De Mello A, Broder DH, Fredlund-Gutierrez J, Chiba S, Pogliano K. Dual localization pathways for the engulfment proteins during Bacillus subtilis sporulation. Mol Microbiol. 2007 Sep;65(6):1534-46. PMID:17824930 doi:http://dx.doi.org/MMI5887
- ↑ Campo N, Marquis KA, Rudner DZ. SpoIIQ anchors membrane proteins on both sides of the sporulation septum in Bacillus subtilis. J Biol Chem. 2008 Feb 22;283(8):4975-82. Epub 2007 Dec 11. PMID:18077456 doi:http://dx.doi.org/10.1074/jbc.M708024200
- ↑ Camp AH, Losick R. A novel pathway of intercellular signalling in Bacillus subtilis involves a protein with similarity to a component of type III secretion channels. Mol Microbiol. 2008 Jul;69(2):402-17. doi: 10.1111/j.1365-2958.2008.06289.x. PMID:18485064 doi:http://dx.doi.org/10.1111/j.1365-2958.2008.06289.x
- ↑ Meisner J, Wang X, Serrano M, Henriques AO, Moran CP Jr. A channel connecting the mother cell and forespore during bacterial endospore formation. Proc Natl Acad Sci U S A. 2008 Sep 30;105(39):15100-5. doi:, 10.1073/pnas.0806301105. Epub 2008 Sep 23. PMID:18812514 doi:http://dx.doi.org/10.1073/pnas.0806301105
- ↑ Meisner J, Maehigashi T, Andre I, Dunham CM, Moran CP Jr. Structure of the basal components of a bacterial transporter. Proc Natl Acad Sci U S A. 2012 Apr 3;109(14):5446-51. Epub 2012 Mar 19. PMID:22431613 doi:10.1073/pnas.1120113109
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