The soluble HIV-1 Vpu protein interacts with calmodulin in a Ca²⁺-dependent manner.

ABSTRACT: The HIV-1-encoded membrane protein Vpu plays key roles in virus lifecycle. Our lab recently revealed a soluble form of Vpu, and we strived to determine its possible physiological function. Here, we provide solid experimental proof that soluble Vpu interacts with Ca²⁺-bound calmodulin (Ca²⁺-CaM). A putative CaM-binding motif in Vpu was predicted, but there was no experimental evidence of the Vpu-CaM association. We applied double electron electron-resonance (DEER) and protein spin labeling to detect the soluble Vpu-CaM complex. We found that soluble full-length and truncated C-terminal region of Vpu directly interact with Ca²⁺-CaM. DEER results from the spin-labeled double cysteine mutant S39C/A103C of CaM showed that upon association with Vpu Ca²⁺

SUBMITTER: Ishola O 

PROVIDER: S-EPMC12262824 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature