8.A.232.  The Phospholipase A (PlaA)/Accesory Protein (PlaS) (PlaAS) Family 

Phosphatase A1 accessory protein PlaS from Serratia marcescens controls cell membrane permeability, fluidity, hydrophobicity, and fatty acid composition in Escherichia coli BL21.  Li et al. 2023 studied the impact of the accessory protein encoded by plaS from Serratia marcescens on PlaA activity in Escherichia coli. PlaS can enhance PlaA activity while concurrently exhibiting inhibitory effects on the growth of E. coli BL21. PlaS can heighten both the permeability of outer and inner cell membranes, leading to concomitant reductions in membrane fluidity and surface hydrophobicity. This phenomenon was validated through scanning electron microscopy (SEM) analysis, which highlights PlaS's capacity to compromise membrane integrity. Through a comparative transcriptomic sequencing approach, Li et al. 2023 identified four down-regulated genes (galM, ybhC, ldtC, and kdpB) alongside two up-regulated genes (rbsB and degP). These genes are intricately associated with processes such as cell membrane synthesis and modification, energy metabolism, and transmembrane transport. These investigations unveil the intricate gene-level mechanisms underpinning PlaS-mediated growth inhibition and membrane disruption. 


 

References:

Li, X., J. Zhou, R. Han, F. Yu, K. Liu, M. Zhao, Y. Liu, Z. Xue, and S. Zhao. (2023). Phosphatase A1 accessory protein PlaS from Serratia marcescens controls cell membrane permeability, fluidity, hydrophobicity, and fatty acid composition in Escherichia coli BL21. Int J Biol Macromol 253: 126776. [Epub: Ahead of Print]

Examples:

TC#NameOrganismal TypeExample
8.A.232.1.1

The PlaS-regulated PlaA phospholipase of 321 aas with possibly 4 or 5 TMSs, with one at the N-terminus, one at residues 50 - 70, and two or three closely together at residues 180 - 240. This enzyme is activated by an accessory protein, PlaS of 257 aas with one N-terminal TMS, possibly with an additional TMS near the C-terminus.  See the family description for details (Li et al. 2023). PlaS may be a distant member of TC family 8.A.28.

PlaA/PlaS of Serratia marcescens