Chlamydia are bacteria that can infect human and animal cells. Human health is particularly affected by Chlamydia pneumoniae (Cpn) and Chlamydia trachomatis. Chlamydia pneumoniae attacks the upper and lower respiratory tract and causes bronchitis, sinusitis and chest infections. Importantly, infections with this bacterium are associated with many chronic diseases such as chronic bronchitis, asthma, atherosclerosis and Alzheimer's disease.
Chlamydia multiply only inside of human cells. To do so, they first have to bind to the host cell from the outside and then enter the cell in a second step. Each cell is surrounded by a membrane known as the 'plasma membrane'. This membrane comprises lots of individual molecules called 'phospholipids'. There are also membrane proteins, which are responsible for transporting materials between the cell interior and the outer environment as well as for intercellular communication. One component of the membrane is the phospholipid phosphatidylserine, or 'PS' for short. In healthy cells, it is located on the inner membrane leaflet, but if the cell is diseased, it is transported to the external membrane leaflet. Here, PS serves as a marker for programmed cell death (apoptosis).
A protein called LIPP was discovered in Cpn that plays a key role in the binding of the bacterium to a human cell. This protein is located on the surface of the bacterium. In earlier studies, the researchers found that a chlamydial infection with Cpn is increased substantially if LIPP is added artificially.
One of their findings was that the LIPP protein binds directly to the plasma membrane and traverses the membrane after binding. Several LIPP molecules then form a pore in the plasma membrane.
Next, however, the bound LIPP transports the PS molecule, normally located on the inner membrane leaflet, to the outside. LIPP was the first protein to be identified that transports a component of the inner membrane leaflet to the surface of the cell when added externally. Surprisingly, this does not trigger cell death. Instead, the cell remains viable. This applies both to cells confronted only with the LIPP proteins and to those also infected with Chlamydia.
The research team proposes that it is beneficial for the Chlamydium to transport the PS molecule of the host cell outward using its LIPP protein. Possibly, at the place where the PS with the LIPP protein is located on the membrane, the membrane is so deformed that the Chlamydium can enter the cell more easily. It is also possible that the PS molecules transported to the outer membrane leaflet of the human cell serve as a receptor for the bacterium.
The first author of the study, had this to say about the prospects arising from these findings: "The LIPP protein has now become a possible target to prevent a chlamydial infection. If we succeed in coming up with a drug that restricts the function of the LIPP protein, it may be possible to prevent the infection." Likewise it is now possible to examine whether other pathogens have a tool similar to Chlamydia that they use to enter human cells. "If this were the case, it could form the basis for an extensive strategy against pathogenic bacteria," emphasises the senior author.
https://www.uni-duesseldorf.de/home/startseite/news-detailansicht-inkl-gb/article/wie-chlamydien-sich-den-zugang-zu-menschlichen-zellen-verschaffen.html
https://www.nature.com/articles/s41467-019-12419-8
A new mechanism for Chlamydia to enter human cells
- 1,152 views
- Added
Edited
Latest News
A new gene-editing system
By newseditor
Posted 23 May
How ketamine's molecular ac…
By newseditor
Posted 23 May
Therapeutic avenues in bone…
By newseditor
Posted 23 May
Linking key nutrients with…
By newseditor
Posted 23 May
Ferroptosis in fatal COVID-…
By newseditor
Posted 22 May
Other Top Stories
New mechanism of cell death in Alzheimer's disease
Read more
Rare DNA alterations linked to type 2 diabetes
Read more
Defects in cilia can cause a common heart valve condition
Read more
Climate change affects the genetic diversity of a species
Read more
Artificial intelligence identifies link between junk DNA and autism
Read more
Protocols
Efficient expansion and CRI…
By newseditor
Posted 21 May
Massively parallel in vivo…
By newseditor
Posted 20 May
Breast cancer-on-chip for p…
By newseditor
Posted 16 May
Methods for making and obse…
By newseditor
Posted 15 May
Mime-seq 2.0: a method to s…
By newseditor
Posted 13 May
Publications
Patterning and folding of i…
By newseditor
Posted 23 May
Peri-ictal activation of do…
By newseditor
Posted 23 May
Ancestry, ethnicity, and ra…
By newseditor
Posted 23 May
Ketamine can produce oscill…
By newseditor
Posted 23 May
Upregulation of neuronal ER…
By newseditor
Posted 23 May
Presentations
Hydrogels in Drug Delivery
By newseditor
Posted 12 Apr
Lipids
By newseditor
Posted 31 Dec
Cell biology of carbohydrat…
By newseditor
Posted 29 Nov
RNA interference (RNAi)
By newseditor
Posted 23 Oct
RNA structure and functions
By newseditor
Posted 19 Oct
Posters
A chemical biology/modular…
By newseditor
Posted 22 Aug
Single-molecule covalent ma…
By newseditor
Posted 04 Jul
ASCO-2020-HEALTH SERVICES R…
By newseditor
Posted 23 Mar
ASCO-2020-HEAD AND NECK CANCER
By newseditor
Posted 23 Mar
ASCO-2020-GENITOURINARY CAN…
By newseditor
Posted 23 Mar