Musiol E, Fromme T, Hau J, Di Pizio A, Klingenspor M. Comparative functional analysis reveals differential nucleotide sensitivity between human and mouse UCP1.
Acta Physiol (Oxf) 2024;
240:e14209. [PMID:
39072954 DOI:
10.1111/apha.14209]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 07/15/2024] [Accepted: 07/16/2024] [Indexed: 07/30/2024]
Abstract
AIM
Mitochondrial uncoupling protein 1 (UCP1) is a unique protein of brown adipose tissue. Upon activation by free fatty acids, UCP1 facilitates a thermogenic net proton flux across the mitochondrial inner membrane. Non-complexed purine nucleotides inhibit this fatty acid-induced activity of UCP1. The most available data have been generated from rodent model systems. In light of its role as a putative pharmacological target for treating metabolic disease, in-depth analyses of human UCP1 activity, regulation, and structural features are essential.
METHODS
In the present study, we established a doxycycline-regulated cell model with inducible human or murine UCP1 expression and conducted functional studies using respirometry comparing wild-type and mutant variants of human UCP1.
RESULTS
We demonstrate that human and mouse UCP1 exhibit similar specific fatty acid-induced activity but a different inhibitory potential of purine nucleotides. Mutagenesis of non-conserved residues in human UCP1 revealed structural components in α-helix 56 and α-helix 6 crucial for uncoupling function.
CONCLUSION
Comparative studies of human UCP1 with other orthologs can provide new insights into the structure-function relationship for this mitochondrial carrier and will be instrumental in searching for new activators.
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