EspF of Enteropathogenic Escherichia coli Binds Sorting Nexin 9

Abstract

EspF of enteropathogenic Escherichia coli targets mitochondria and subverts a number of cellular functions. EspF consists of six putative Src homology 3 (SH3) domain binding motifs. In this study we identified sorting nexin 9 (SNX9) as a host cell EspF binding partner protein, which binds EspF via its amino-terminal SH3 region. Coimmunoprecipitation and confocal microscopy showed specific EspF-SNX9 interaction and nonmitochondrial protein colocalization in infected epithelial cells.

Screening for Host Proteins Interacting with Escherichia Coli O157:H7 EspF using Bimolecular Fluorescence Complementation

“…Enrichment analysis showed that the target proteins were enriched in five main types of MF: ribosome structure (p = 0.012), GTPase activity (p = 0.013), protein binding (p = 0.030), RNA binding (p = 0.038) and RNA splicing activity (p = 0.048; Table 3). Studies have shown that EspF has the ability to target mitochondria and nucleoli [6,16], and interacts with N-WASP, SNX9 and Abcf2 [8,[17][18], leading to microvilli disappearance, cytoskeleton rearrangement, actin aggregation, mitochondrial dysfunction and apoptosis in intestinal epithelial cells, nucleolysis and other functions [11,39]. EspF with GTPase activity combined with splicing RNA and other functions in the host cell remains unknown research territory, deserving of further investigation.…”

“…The number of reads is proportional to the intensity of the interaction between proteins. As is known, SNX9 has been demonstrated to interact with EspF [17]; we have indeed screened it, but it was not obvious in the cloud because the number of reads was not high. We suspect that the expression of this protein may be low, although an interaction may not be apparent because the number of reads is not high.…”

“…Such structural features enable EspF to target the mitochondria, resulting in disruption of the mitochondrial membrane potential, release of cytochrome c into the cytoplasm, cleavage of caspases 9 and 3; all of these events are associated with mitochondrial apoptotic signaling pathways [15,16]. However, the SH3 and CRIB domains enable EspF to interact with the SNX9 protein and the neuronal Wiskott-Aldrich syndrome (N-WASP) protein directly [17,18]. Moreover, VK Viswanathan et al have shown that EspF can interact with the host intermediate filament protein cytokeratin 18 (CK18) in a complex with adaptor protein 14-3-3, which can alter the architecture of the intermediate filament network in EPEC-infected cells [19].…”

Interaction of the Wiskott–Aldrich syndrome protein with sorting nexin 9 is required for CD28 endocytosis and cosignaling in T cells

“…SNX9 has been implicated in many cellular functions, having been shown, for example, to bind Ack2 so as to modulate epidermal growth factor degradation and potentially Drosophila axonal guidance (31,32) and to interact with the Escherichia coli EpsF protein to potentially regulate EpsF pathophysiologic effects (41). SNX9 also mediates transferrin endocytosis and binds to and stimulates GTPase activity of dynamins 1 and 2, promoting dynamin-mediated formation and maturation of clathrin-coated pits (30,33).…”

Insulin receptor tyrosine kinase substrate links theE. coliO157:H7 actin assembly effectors Tir and EspFUduring pedestal formation

“…Like EspF U , EspF consists of an N-terminal translocation domain and several 47-residue Cterminal repeats, each of which contains an N-WASP binding segment and a proline-rich sequence that is recognized by an SH3 domain-containing protein that binds and deforms membranes. In the case of EspF, the SH3-containing protein is SNX9 (29,30), which contains a BAR domain and participates in membrane remodeling during endocytosis (31). Although EspF U can complement some functions of EspF (32), EspF plays no apparent role in pedestal formation (15), presumably because its proline-rich sequences target a different SH3 domain.…”