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Updated: Aug 16, 2026

Identification of Functional Protein Regions Through Chimeric Protein Construction
Published on: January 8, 2019
Presence of a cytoplasmic retention sequence within the human interleukin-1alpha precursor
Makoto Sudo1, Yoshiro Kobayashi, Naoko Watanabe
1Department of Biomolecular Science, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
Abstract:
Interleukin (IL)-1alpha is primarily translated as a 33 kDa molecule (IL-1alpha1-271), and then processed into a 17 kDa molecule (IL-1alpha119-271) by calpain. The precursor region of IL-1alpha (IL-1 alpha1-118) contains a nuclear localization signal (KVLKKRRL, residues 79-86). We investigated the intracellular localization of IL-1alpha fused with green fluorescent protein or beta-galactosidase. IL-1alpha1-118 was localized exclusively in the nucleus, but IL-1 alpha1-271 in both the nucleus and the cytoplasm, suggesting the presence of a cytoplasmic retention signal within the mature region of IL-1alpha. Furthermore, the intracellular localization of IL-1alpha with deletions from the C terminus, internal deletions and point mutations suggested that the cytoplasmic retention signal is located within residues 168-201.
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