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Topological analysis and role of the transmembrane domain in polar targeting of PilS, a Pseudomonas aeruginosa sensor kinase
Author(s) -
Ethier Julie,
Boyd Jessica M.
Publication year - 2000
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2000.02189.x
Subject(s) - transmembrane protein , biology , transmembrane domain , microbiology and biotechnology , cytoplasm , pilin , topology (electrical circuits) , membrane topology , pilus , membrane protein , biophysics , biochemistry , membrane , gene , escherichia coli , receptor , mathematics , combinatorics
In Pseudomonas aeruginosa , synthesis of pilin, the major protein subunit of the pili, is regulated by a two‐component signal transduction system in which PilS is the sensor kinase. PilS is an inner membrane protein found at the poles of the bacterial cell. It is composed of three domains: an N‐terminal hydrophobic domain; a central cytoplasmic linker region; and the C‐terminal transmitter region conserved among other sensor kinases. The signal that activates PilS and, consequently, pilin transcription remains unknown. The membrane topology of the hydrophobic domain was determined using the lacZ and phoA gene fusion approach. In this report, we describe a topological model for PilS in which the hydrophobic domain forms six transmembrane helices, whereas the N‐ and C‐termini are cytoplasmic. This topology is very stable, and the cytoplasmic C‐terminus cannot cross the inner membrane. We also show that two of the six transmembrane segments are sufficient for membrane anchoring and polar localization of PilS.