Eeyarestatin 24 impairs SecYEG‐dependent protein trafficking and inhibits growth of clinically relevant pathogens

Abstract

Eeyarestatin 1 (ES1) is an inhibitor of endoplasmic reticulum (ER) associated protein degradation, Sec61‐dependent Ca2+ homeostasis and protein translocation into the ER. Recently, evidence was presented showing that a smaller analog of ES1, ES24, targets the Sec61‐translocon, and captures it in an open conformation that is translocation‐incompetent. We now show that ES24 impairs protein secretion and membrane protein insertion in Escherichia coli via the homologous SecYEG‐translocon. Transcriptomic analysis suggested that ES24 has a complex mode of action, probably involving multiple targets. Interestingly, ES24 shows antibacterial activity toward clinically relevant strains. Furthermore, the antibacterial activity of ES24 is equivalent to or better than that of nitrofurantoin, a known antibiotic that, although structurally similar to ES24, does not interfere with SecYEG‐dependent protein trafficking. Like nitrofurantoin, we find that ES24 requires activation by the NfsA and NfsB nitroreductases, suggesting that the formation of highly reactive nitroso intermediates is essential for target inactivation in vivo.

Membrane protein biogenesis at the ER: the highways and byways

“…Hence, via the study of individual proteins [6,97,104] together with a global proteomics-based approach [103], it was the resistance of type III and type III-like TMPs to such compounds which revealed a previously unanticipated level of complexity that was incompatible with the prevailing models of TMP biogenesis [7,8,83]. Given that many of the TMP clients of the Sec61 complex are drug targets [133], Sec61 inhibitors are promising candidates for therapeutic development; particularly since they appear well tolerated in vivo [134][135][136][137] and have demonstrated promising analgesic [134], antibacterial [138], anti-inflammatory [135], antitumour [136] and antiviral [139][140][141] activity.…”

The Dynamic SecYEG Translocon

“…The mammalian Sec61 complex is also inhibited by lanthanum ions, which stabilize the Sec61 channel in its open state (Erdmann et al, 2009). Components that inhibit both the eukaryotic Sec61 complex and the bacterial SecYEG complex are the glycoresin Ipomoeassin F (IpomF) (Zong et al, 2019;Steinberg et al, 2020), eeyarestatin Steenhuis et al, 2021) and decatransin (Junne et al, 2015;Kalies and Römisch, 2015). IpomF was isolated from the morning glory Ipomea squamosa and shown to bind most likely near the lateral gate of Sec61α (Zong et al, 2019).…”

“…Eeyarestatin I (ESI) was initially discovered as inhibitor of the retrograde protein transport into the endoplasmic reticulum and then shown to inhibit co-translational protein transport by the Sec61 complex . ESI does not inhibit growth of E. coli, but a smaller variant of ESI, ES24 (Gamayun et al, 2019), is active against E. coli and several clinically relevant pathogens (Steenhuis et al, 2021). ES24 likely binds to the cytosolic part of the lateral gate (Gamayun et al, 2019), but the antibacterial activity depends on the presence of the nitroreductases NfsA and NfsB, indicating that a specific reduction step is required to activate ES24 (Steenhuis et al, 2021).…”

“…ESI does not inhibit growth of E. coli, but a smaller variant of ESI, ES24 (Gamayun et al, 2019), is active against E. coli and several clinically relevant pathogens (Steenhuis et al, 2021). ES24 likely binds to the cytosolic part of the lateral gate (Gamayun et al, 2019), but the antibacterial activity depends on the presence of the nitroreductases NfsA and NfsB, indicating that a specific reduction step is required to activate ES24 (Steenhuis et al, 2021). Decatransin is a naturally occurring fungal decadepsipeptide that was identified in a cancer drug screen and later shown to inhibit SecYEG/Sec61.…”

Inhibitors of the Sec61 Complex and Novel High Throughput Screening Strategies to Target the Protein Translocation Pathway

“…Recently, an antibacterial activity of ES24, a smaller analog of ESI, was described. ES24 impairs protein translocation in E. coli via interaction with the SecYEG translocon, the prokaryotic orthologue of the Sec61 translocon [ 184 ].…”