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Ceru 2010 J Biol Chem

From Bioblast
Publications in the MiPMap
Ceru S, Konjar S, Maher K, Repnik U, Krizaj I, Bencina M, Renko M, Nepveu A, Zerovnik E, Turk B, Kopitar-Jerala N (2010) Stefin B interacts with histones and cathepsin L in the nucleus. J Biol Chem 285:10078-86.

Β» PMID: 20075068 Open Access

Ceru S, Konjar S, Maher K, Repnik U, Krizaj I, Bencina M, Renko M, Nepveu A, Zerovnik E, Turk B, Kopitar-Jerala N (2010) J Biol Chem

Abstract: Stefin B (cystatin B) is an endogenous inhibitor of cysteine proteinases localized in the nucleus and the cytosol. Loss-of-function mutations in the stefin B gene (CSTB) gene were reported in patients with Unverricht-Lundborg disease (EPM1). We have identified an interaction between stefin B and nucleosomes, specifically with histones H2A.Z, H2B, and H3. In synchronized T98G cells, stefin B co-immunoprecipitated with histone H3, predominantly in the G(1) phase of the cell cycle. Stefin B-deficient mouse embryonic fibroblasts entered S phase earlier than wild type mouse embryonic fibroblasts. In contrast, increased expression of stefin B in the nucleus delayed cell cycle progression in T98G cells. The delay in cell cycle progression was associated with the inhibition of cathepsin L in the nucleus, as judged from the decreased cleavage of the CUX1 transcription factor. In vitro, inhibition of cathepsin L by stefin B was potentiated in the presence of histones, whereas histones alone did not affect the cathepsin L activity. Interaction of stefin B with the Met-75 truncated form of cathepsin L in the nucleus was confirmed by fluorescence resonance energy transfer experiments in the living cells. Stefin B could thus play an important role in regulating the proteolytic activity of cathepsin L in the nucleus, protecting substrates such as transcription factors from its proteolytic processing.


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Organism: Mouse