Lasa

lasA is a gene in Pseudomonas aeruginosa that encodes the extracellular protease LasA, also known as elastase A. The enzyme is secreted into the surrounding environment and cleaves elastin and other host proteins, contributing to tissue damage during infection. LasA is part of the bacterium’s virulence arsenal and often acts in concert with LasB elastase to disrupt connective tissue and modulate immune components, aiding bacterial spread within host tissues.

Expression of lasA is regulated by the Las quorum-sensing system, which includes the autoinducer synthase LasI and the transcriptional regulator LasR. As cell density increases, LasR activates transcription of lasA alongside lasB and other Las-regulated genes, integrating LasA production into the broader virulence program.

Genetically, lasA is located on the chromosome of P. aeruginosa and encodes a secreted protease. The gene is frequently studied together with lasB and other components of the Las regulon. The protease activity of LasA is typically assessed using elastolytic assays, and its activity contributes to elastin degradation observed in infected tissues.

Clinical relevance: LasA contributes to pathology in both acute and chronic P. aeruginosa infections, including lung infections in cystic fibrosis patients. Because of its role in tissue damage, LasA is a target of antivirulence research, with approaches aimed at inhibiting its activity or interfering with LasR-mediated expression.