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Characterization of the Role of Transmembrane Protein hTMEM205 in Pt(II)‐drug Resistance and Extrusion
Author(s) -
Qasim Tahir,
Gallenito Marc,
Pope Mitchell,
Tutol Jasmine,
Prakash Ved,
Dodani Sheel,
Meloni Gabriele
Publication year - 2021
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2021.35.s1.03249
Platinum‐coordination complexes are effective chemotherapeutic drugs for the treatment of tumors, but cancer cells can develop drug resistance leading to treatment failure and relapse. Drug uptake and extrusion by transmembrane transporter proteins are critical in controlling intracellular Pt(II)‐drug concentrations and thus in developing pre‐target resistance. Human TMEM205 (hTMEM205) is a transmembrane protein overexpressed in cisplatin‐resistant cancer cells. In this work, we utilized a high‐throughput recombinant expression platform in E. coli coupled to in vivo functional resistance assays to study the elusive hTMEM205 molecular function in mediating resistance against Pt(II)‐drugs. By conducting quantitative analysis of the effects of Pt(II)‐coordination complexes on cellular growth and filamentation in E. coli cells expressing hTMEM205, and coupling it with Pt quantification and cellular profiling, we demonstrate that hTMEM205 mediates selective cisplatin and oxaliplatin cellular export, but not carboplatin. By introducing selective mutations of conserved transmembrane residues we reveal that hTMEM205 recognizes and mediates Pt(II)‐extrusion via a putative sulfur‐based translocation mechanism, thereby contributing to pre‐target resistance. Thus, hTMEM205 represents a potential target that can be exploited to reduce cellular resistance towards Pt(II)‐drugs. Through the Secreted Protein Discovery Initiative (SPDI) and protein interaction networks, an interaction was hypothesized between TMEM52B, an uncharacterized transmembrane protein, and TMEM205. Protein structure predictions and known Pt(II)‐binding motifs highly suggest that TMEM52B can not only bind these metals but may be involved in their delivery to TMEM205 or the regulation of TMEM205′s function. We hope to elucidate their combined effect on Pt(II)‐coordination complex resistance by characterizing TMEM52B's metal binding properties and the effect of the interaction on TMEM205‐mediated transport kinetics and thermodynamics.