N-terminus-independent activation of c-Src via binding to a tetraspan(in) TM4SF5 in hepatocellular carcinoma is abolished by the TM4SF5 C-terminal peptide application

Abstract

Active c-Src non-receptor tyrosine kinase localizes to the plasma membrane via N-terminal lipid modification. Membranous c-Src causes cancer initiation and progression. Even though transmembrane 4 L six family member 5 (TM4SF5), a tetraspan(in), can be involved in this mechanism, the molecular and structural influence of TM4SF5 on c-Src remains unknown. Methods: Here, we investigated molecular and structural details by which TM4SF5 regulated c-Src devoid of its N-terminus and how cell-penetrating peptides were able to interrupt c-Src activation via interference of c-Src-TM4SF5 interaction in hepatocellular carcinoma models. Results: The TM4SF5 C-terminus efficiently bound the c-Src SH1 kinase domain, efficiently to the inactively-closed form. The complex involved protein tyrosine phosphatase 1B able to dephosphorylate Tyr530. The c-Src SH1 domain alone, even in a closed form, bound TM4SF5 to cause c-Src Tyr419 and FAK Y861 phosphorylation. Homology modeling and molecular dynamics simulation studies predicted the directly interfacing residues, which were further validated by mutational studies. Cell penetration of TM4SF5 C-terminal peptides blocked the interaction of TM4SF5 with c-Src and prevented c-Src-dependent tumor initiation and progression in vivo. Conclusions: Collectively, these data demonstrate that binding of the TM4SF5 C-terminus to the kinase domain of inactive c-Src leads to its activation. Because this binding can be abolished by cell-penetrating peptides containing the TM4SF5 C-terminus, targeting this direct interaction may be an effective strategy for developing therapeutics that block the development and progression of hepatocellular carcinoma.

Liver‐originated small extracellular vesicles with TM4SF5 target brown adipose tissue for homeostatic glucose clearance

“…T 5 ERMs), similar to tetraspanin‐enriched microdomains (Charrin et al., 2009; Yanez‐Mo et al., 2009). TM4SF5 in hepatocytes binds integrins (Choi et al., 2009), EGFR (Kim et al., 2017), CD151(Kang et al., 2014), CD44 (Lee et al., 2015), mTOR (Jung et al., 2019), FAK (Jung et al., 2012), c‐Src (Song et al., 2021) and transporters for nutrients including amino acids (Jung et al., 2019; Kim et al., 2019) and glucose (this study). Based on such TM4SF5 characteristics, the packaging of specific membrane proteins and/or receptors into liv/hep‐sEV Tm4sf5 might be achieved via protein–protein associations within T 5 ERMs.…”

Systemic TM4SF5 overexpression in ApcMin/+ mice promotes hepatic portal hypertension associated with fibrosis

“…Further, CD133 can trigger Akt activation, pS 9 GSK3β and β-catenin stabilization, and transcriptional activation of CD44 and TM4SF5 . The translational product TM4SF5 is located at membranes and activates c-Src ( 32 ), which phosphorylates STAT3 at Tyr705 ( 33 ) or CD133 at Tyr828/Tyr858 ( 34 ). TM4SF5 ( 3 ) and phosphorylated CD133-mediated PI3K activity allows Akt1 to be activated for pS 9 GSK3β ( 35 ).…”

Glucose‐mediated mitochondrial reprogramming by cholesterol export at TM4SF5‐enriched mitochondria‐lysosome contact sites

“…Our previously constructed model structure of hTM4SF5 [ 25 ] was utilized to show the cholesterol binding mode. Molecular graphic figures were generated using PyMOL v.2.5.2 software (Schrödinger, LLC).…”