Open AccessSteC and the intracellular Salmonella ‐induced F‐actin meshwork
Author(s) -
Heggie Alison,
Cerny Ondrej,
Holden David W.
Publication year - 2021
Publication title -
cellular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.542
H-Index - 138
eISSN - 1462-5822
pISSN - 1462-5814
DOI - 10.1111/cmi.13315
Subject(s) - biology , actin , salmonella enterica , microbiology and biotechnology , actin cytoskeleton , effector , secretion , intracellular , vacuole , phosphorylation , myosin , kinase , salmonella , cytoskeleton , cytoplasm , bacteria , biochemistry , genetics , cell
Salmonella enterica serovars infect a broad range of mammalian hosts including humans, causing both gastrointestinal and systemic diseases. Following uptake into host cells, bacteria replicate within vacuoles ( Salmonella‐ containing vacuoles; SCVs). Clusters of SCVs are frequently associated with a meshwork of F‐actin. This meshwork is dependent on the Salmonella pathogenicity island 2 encoded type III secretion system and its effector SteC. SteC contains a region with weak similarity to conserved subdomains of eukaryotic kinases and has kinase activity that is required for the formation of the F‐actin meshwork. Several substrates of SteC have been identified. In this mini‐review, we attempt to integrate these findings and propose a more unified model to explain SCV‐associated F‐actin: SteC (i) phosphorylates the actin sequestering protein Hsp27, which increases the local G‐actin concentration (ii) binds to and phosphorylates formin family FMNL proteins, which enables actin polymerisation and (iii) phosphorylates MEK, resulting in activation of the MEK/ERK/MLCK/Myosin II pathway, leading to F‐actin bundling. We also consider the possible physiological functions of SCV‐associated F‐actin and similar structures produced by other intracellular bacterial pathogens.