Acinetobacter baumannii Regulates Bacterial Motility Through PilZ-containing Proteins
Location
D.P. Culp Center Ballroom
Start Date
4-5-2024 9:00 AM
End Date
4-5-2024 11:30 AM
Poster Number
106
Name of Project's Faculty Sponsor
Erik Petersen
Faculty Sponsor's Department
Health Sciences
Competition Type
Competitive
Type
Poster Presentation
Presentation Category
Health
Abstract or Artist's Statement
Acinetobacter baumannii is an emerging nosocomial pathogen that has acquired multi-drug resistance in remarkable time and positioned itself at the forefront of concern for healthcare professionals and researchers alike. This multi-drug resistance in combination with its unprecedented ability to survive desiccation on surfaces help illustrate how and why A. baumannii has become such a formidable pathogen. Another key mechanism that A. baumannii and numerous other bacteria have at their disposal when it comes to infections, spreading, and navigating their environment is motility. While A. baumannii lacks flagella used to swim in liquids, it encodes type IV pili that can be used in twitching motility along semisolid substrates. Some A. baumannii strains use these pili to move across the top of agar surfaces, while other strains require a solid, plastic surface in which to crawl across. The machinery used to power, extend, and retract these type IV pili is tightly regulated in response to changing environmental cues. In particular, the bacterial second messenger cyclic-di-GMP is often used to regulate transitions between being sessile and motile. In other bacteria, this regulation can use PilZ domains that appear in numerous proteins and tend to bind cyclic-di-GMP. We used bioinformatic tools to identify two PilZ-containing proteins within A. baumannii. Deletion of either of these two PilZ domain-containing proteins severely inhibited surface-associated motility, while at least one is required for movement along a plastic surface. Notably, one of these proteins appears to be a homolog of the PilZ protein for which the domain is named. This protein has been demonstrated to play a role in regulating motility in other bacteria. Interestingly, although cyclic-di-GMP appears to regulate this motility, preliminary analysis of cyclic-di-GMP binding by our PilZ-containing proteins using a fluorescent biosensor suggests neither protein may bind cyclic-di-GMP. While there is precedent for this in scientific literature, further testing will be required to determine whether this is the case. Future work using mutants of these proteins will help to determine how they participate in the regulation of pilus-mediated motility in A. baumannii.
Acinetobacter baumannii Regulates Bacterial Motility Through PilZ-containing Proteins
D.P. Culp Center Ballroom
Acinetobacter baumannii is an emerging nosocomial pathogen that has acquired multi-drug resistance in remarkable time and positioned itself at the forefront of concern for healthcare professionals and researchers alike. This multi-drug resistance in combination with its unprecedented ability to survive desiccation on surfaces help illustrate how and why A. baumannii has become such a formidable pathogen. Another key mechanism that A. baumannii and numerous other bacteria have at their disposal when it comes to infections, spreading, and navigating their environment is motility. While A. baumannii lacks flagella used to swim in liquids, it encodes type IV pili that can be used in twitching motility along semisolid substrates. Some A. baumannii strains use these pili to move across the top of agar surfaces, while other strains require a solid, plastic surface in which to crawl across. The machinery used to power, extend, and retract these type IV pili is tightly regulated in response to changing environmental cues. In particular, the bacterial second messenger cyclic-di-GMP is often used to regulate transitions between being sessile and motile. In other bacteria, this regulation can use PilZ domains that appear in numerous proteins and tend to bind cyclic-di-GMP. We used bioinformatic tools to identify two PilZ-containing proteins within A. baumannii. Deletion of either of these two PilZ domain-containing proteins severely inhibited surface-associated motility, while at least one is required for movement along a plastic surface. Notably, one of these proteins appears to be a homolog of the PilZ protein for which the domain is named. This protein has been demonstrated to play a role in regulating motility in other bacteria. Interestingly, although cyclic-di-GMP appears to regulate this motility, preliminary analysis of cyclic-di-GMP binding by our PilZ-containing proteins using a fluorescent biosensor suggests neither protein may bind cyclic-di-GMP. While there is precedent for this in scientific literature, further testing will be required to determine whether this is the case. Future work using mutants of these proteins will help to determine how they participate in the regulation of pilus-mediated motility in A. baumannii.