Shigella, a bacterial pathogen that causes dysentery and is the main explanation for childhood diarrheal ailments, inserts a pore known as a translocon into an contaminated individual’s intestinal cells after which injects bacterial proteins into the cells. There, the proteins hijack the cells’ equipment to assist Shigella multiply. In a research revealed in mBio, a group at Massachusetts General Hospital (MGH) has uncovered vital particulars about Shigella’s translocon, which can assist researchers develop an efficient technique to dam this vital element of an infection.
“Shigella infects our gut by manipulating our intestinal cells and tricking them into letting the Shigella inside. In fact, there are many bacterial pathogens that use this same, or similar, mechanism to infect us,” says lead creator Poyin Chen, Ph.D., a postdoctoral fellow at MGH. “This translocon pore is essentially the gateway through which bacterial proteins get pumped into our cells. We know that this structure is made of two proteins—IpaB and IpaC—but what we don’t know is how these proteins fit together to make this pore.”
When the investigators used protein mapping methods to look carefully at translocons once they have been embedded in cell membranes, they have been capable of see which of the 2 proteins—particularly IpaB—makes up the interior ring of the pore. “If you think of the translocon pore as a donut, this would be the walls of the donut hole. This finding is important because this is the part of the translocon pore that directly interacts with bacterial proteins as they are injected into our cells,” explains Chen. “With the findings from this study, we can begin to understand if this pore acts as a slippery tube that bacterial proteins travel through or if the translocon pore can control the flow of bacterial proteins into our cells.”
Such particulars could assist investigators goal the translocon and block the entry of Shigella proteins into cells. “For something that is so essential to establishing infection, we know terribly little of how it’s made and how it works,” says Chen. “As we gain a better understanding of its parts, we will be able to approach the structure as a whole and maybe even find ways to neutralize the function of this structure to prevent infection before it can begin.”
Co-authors embody Brian C. Russo, Jeffrey Ok. Duncan-Lowey, Natasha Bitar, Keith Egger and Marcia B. Goldberg.
Topology and contribution to the pore channel lining of plasma membrane embedded S. flexneri sort 3 secretion translocase IpaB, mBio (2021).
Massachusetts General Hospital
New particulars behind how the Shigella pathogen delivers bacterial proteins into our cells (2021, November 23)
retrieved 23 November 2021
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