TY - JOUR
T1 - Molecular architecture, polar targeting and biogenesis of the Legionella Dot/Icm T4SS
AU - Ghosal, Debnath
AU - Jeong, Kwangcheol C.
AU - Chang, Yi Wei
AU - Gyore, Jacob
AU - Teng, Lin
AU - Gardner, Adam
AU - Vogel, Joseph P.
AU - Jensen, Grant J.
N1 - Funding Information:
We thank R. Isberg (Tufts University, Medford, MA, USA) for antibodies that recognize DotF and DotH, E. Buford for technical assistance and P. Levin (Washington University, St Louis, MO, USA) for assistance with deconvolution microscopy. ECT data were recorded at the Beckman Institute Resource Center for Transmission Electron Microcopy at Caltech and the cryo-EM facility at Janelia Research Campus. We thank C. Oikonomou for the creation of the domain maps and for help structuring and revising the text. We also recognize E. Darwin for key suggestions and critical appraisal of this manuscript. This work was funded by the NIH grant R01AI127401 to G.J.J. and the NIH grant R01AI48052 to J.P.V.
Publisher Copyright:
© 2019, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2019/7/1
Y1 - 2019/7/1
N2 - Legionella pneumophila survives and replicates inside host cells by secreting ~300 effectors through the defective in organelle trafficking (Dot)/intracellular multiplication (Icm) type IVB secretion system (T4BSS). Here, we used complementary electron cryotomography and immunofluorescence microscopy to investigate the molecular architecture and biogenesis of the Dot/Icm secretion apparatus. Electron cryotomography mapped the location of the core and accessory components of the Legionella core transmembrane subcomplex, revealing a well-ordered central channel that opens into a large, windowed secretion chamber with an unusual 13-fold symmetry. Immunofluorescence microscopy deciphered an early-stage assembly process that begins with the targeting of Dot/Icm components to the bacterial poles. Polar targeting of this T4BSS is mediated by two Dot/Icm proteins, DotU and IcmF, that, interestingly, are homologues of the T6SS membrane complex components TssL and TssM, suggesting that the Dot/Icm T4BSS is a hybrid system. Together, these results revealed that the Dot/Icm complex assembles in an ‘axial-to-peripheral’ pattern.
AB - Legionella pneumophila survives and replicates inside host cells by secreting ~300 effectors through the defective in organelle trafficking (Dot)/intracellular multiplication (Icm) type IVB secretion system (T4BSS). Here, we used complementary electron cryotomography and immunofluorescence microscopy to investigate the molecular architecture and biogenesis of the Dot/Icm secretion apparatus. Electron cryotomography mapped the location of the core and accessory components of the Legionella core transmembrane subcomplex, revealing a well-ordered central channel that opens into a large, windowed secretion chamber with an unusual 13-fold symmetry. Immunofluorescence microscopy deciphered an early-stage assembly process that begins with the targeting of Dot/Icm components to the bacterial poles. Polar targeting of this T4BSS is mediated by two Dot/Icm proteins, DotU and IcmF, that, interestingly, are homologues of the T6SS membrane complex components TssL and TssM, suggesting that the Dot/Icm T4BSS is a hybrid system. Together, these results revealed that the Dot/Icm complex assembles in an ‘axial-to-peripheral’ pattern.
UR - http://www.scopus.com/inward/record.url?scp=85064764775&partnerID=8YFLogxK
U2 - 10.1038/s41564-019-0427-4
DO - 10.1038/s41564-019-0427-4
M3 - Article
C2 - 31011165
AN - SCOPUS:85064764775
VL - 4
SP - 1173
EP - 1182
JO - Nature Microbiology
JF - Nature Microbiology
SN - 2058-5276
IS - 7
ER -