Related Experiment Video
Updated: Jul 25, 2026
10:59
Enrichment of Bacterial Lipoproteins and Preparation of N-terminal Lipopeptides for Structural Determination by Mass Spectrometry
Published on: May 21, 2018
Lipoprotein processing is required for virulence of Mycobacterium tuberculosis
1Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 30/32, CH-8028 Zürich, Schweiz. psander@immv.unizh.ch
Molecular Microbiology
|June 10, 2004
Summary
Lipoprotein signal peptidase A (LspA) is dispensable for Mycobacterium tuberculosis growth in vitro but crucial for virulence. Disrupting LspA attenuates tuberculosis, highlighting lipoprotein processing as a key factor in pathogenesis and a potential therapeutic target.
Area of Science:
- Microbiology
- Pathogenesis
- Bacterial protein processing
Background:
- Lipoproteins are secreted bacterial proteins with a lipidated N-terminus.
- Processing involves prolipoprotein diacylglyceryl transferase (Lgt) and lipoprotein signal peptidase (LspA).
- LspA function is primarily studied in non-pathogenic bacteria.
Purpose of the Study:
- To investigate the role of LspA in Mycobacterium tuberculosis pathogenesis.
- To determine if LspA is essential for bacterial growth or virulence.
Main Methods:
- Disruption of the lspA gene in Mycobacterium tuberculosis via allelic replacement.
- Assessment of bacterial growth under in vitro culture conditions.
- Evaluation of virulence in established tuberculosis models.
Main Results:
- LspA is dispensable for Mycobacterium tuberculosis growth in vitro.
- The lspA mutant exhibited significant attenuation in virulence models.
- Lipoprotein processing is identified as a critical virulence determinant.
Conclusions:
- Lipoprotein metabolism is a major virulence factor in tuberculosis.
- LspA plays a significant role in bacterial pathogenesis.
- Bacterial lipoprotein signal peptidases represent a potential therapeutic target.
Related Concept Videos
01:38Intralumenal Vesicles and Multivesicular Bodies
Intraluminal vesicles (ILVs) are small vesicles 50-80 nm in diameter formed during the maturation of early endosomes. A specialized endosome containing numerous ILVs is called a multivesicular body (MVB). ILVs contain internalized molecules such as antigens, nucleic acids, proteins, and metabolites. Some of these molecules are released from the MVBs inside exosomes and are transported to other cells. Other MVBs contain molecules that are retained in the ILVs and are later degraded within the...
01:28Pulmonary Tuberculosis II
Tuberculosis, or TB, is a bacterial infectious disease caused by Mycobacterium tuberculosis. While its primary impact is on the lungs, leading to pulmonary tuberculosis, it can also affect various other organs, a condition referred to as extrapulmonary tuberculosis.
Here is a detailed explanation of its pathophysiology:
Transmission: The process begins when a person inhales droplet nuclei containing M. tuberculosis. These are typically released into the air when an individual with pulmonary or...
Here is a detailed explanation of its pathophysiology:
Transmission: The process begins when a person inhales droplet nuclei containing M. tuberculosis. These are typically released into the air when an individual with pulmonary or...
01:19Formation of Lipopolysaccharides
Lipopolysaccharides (LPS) are crucial components of the outer membrane of Gram-negative bacteria, serving both structural and functional roles. It contributes to membrane stability and protects bacteria from host immune responses. LPS is composed of three major regions—lipid A, a core oligosaccharide, and an O antigen. The biosynthesis and assembly of LPS involve a highly coordinated set of enzymatic reactions and transport mechanisms. Additionally, LPS is recognized as an endotoxin, triggering...
01:26Bacterial Translocation and Protein Secretion
Bacterial protein secretion involves translocation systems to ensure proteins reach their designated locations, including the plasma membrane, periplasm, outer membrane, or the external environment. These translocation systems are vital for bacterial physiology, supporting processes like membrane assembly, enzymatic activity in the periplasm, and interactions with the external environment. The division of labor between Sec and Tat pathways ensures efficiency in handling proteins with diverse...
01:28Regulation of Bacterial Virulence
Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...
01:23Tuberculosis
Tuberculosis (TB) remains a significant global health concern, primarily targeting the lungs and spreading through airborne transmission. Infection begins when aerosolized droplet nuclei, expelled by an individual with active TB, are inhaled by another person. These microscopic particles carry Mycobacterium tuberculosis, the causative agent of TB. Upon reaching the alveoli, the bacilli are engulfed by alveolar macrophages. However, due to their specialized lipid-rich cell wall, these pathogens...