Nagasaka K, Nakagawa S, Yano T, Takizawa S, Matsumoto Y, Tsuruga T et al.. Human homolog of Drosophila tumor suppressor Scribble negatively regulates cell-cycle progression from G1 to S phase by localizing at the basolateral membrane in epithelial cells. Cancer Sci 97: 1217-1225

Department of Obstetrics and Gynecology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Cancer Science (Impact Factor: 3.52). 12/2006; 97(11):1217-25. DOI: 10.1111/j.1349-7006.2006.00315.x
Source: PubMed


Drosophila tumor suppressor Scribble has been identified as an apical-basolateral polarity determinant in epithelia. A human homolog of Drosophila Scribble, human Scribble (hScrib), has been identified as a protein targeted by human papillomavirus E6 for the ubiquitin-mediated degradation dependent on E6AP, a cellular ubiquitin-protein ligase. Human Scribble is classified as a LAP protein, having leucine-rich repeats (LRRs) and PDZ domains. We investigated whether hScrib, which is thought to have a role in polarity determination based on the data of its Drosophila homolog, is involved in cell-cycle regulation and proliferation control of epithelia. Transfection of hScrib inhibits cell-cycle progression from G1 to S phase, and it up- and down-regulates expression of adenomatous polyposis coli and cyclins A and D1, respectively. Knockdown of hScrib expression by siRNA leads to cell-cycle progression from G1 to S phase. We explored functional domain mapping to reveal which domains of hScrib are critical for its cellular proliferation control and localization at the basolateral membrane. We found that LRRs and PDZ domain 1 are indispensable for hScrib to inhibit cell growth by blocking cell-cycle progression and to keep its proper localization. These data indicate that basolateral membrane localization of hScrib is closely related to its proliferation control. Our findings suggest the possibility that hScrib is involved in signal transduction to negatively regulate cell proliferation by localizing at the basolateral membrane of epithelial cells through LRRs and PDZ domains.

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Available from: Osamu Hiraike, Sep 26, 2014
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    • "The following siRNA sequences were used: the sequence for Scrib siRNA was 5_CCAGCCAAUGUGAAGCAGGCGUAUA-3 with a control siRNA selected by Life Technologies. For plasmid transfection, using Lipofectamine LTX with Plus reagents (Life Technologies), pCMV-EGFP-Scrib plasmid (Nagasaka et al., 2006) or empty pCMV-EGFP plasmid as a control was transfected into satellite cell-derived myoblasts at 50‒60% confluence in adherence condition. "
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    ABSTRACT: Satellite cells are resident skeletal muscle stem cells that supply myonuclei for homeostasis, hypertrophy, and repair in adult muscle. Scrib is one of the major cell-polarity proteins, acting as a potent tumor suppressor in epithelial cells. Here, we show that Scrib also controls satellite-cell-fate decisions in adult mice. Scrib is undetectable in quiescent cells but becomes expressed during activation. Scrib is asymmetrically distributed in dividing daughter cells, with robust accumulation in cells committed to myogenic differentiation. Low Scrib expression is associated with the proliferative state and preventing self-renewal, whereas high Scrib levels reduce satellite cell proliferation. Satellite-cell-specific knockout of Scrib in mice causes a drastic and insurmountable defect in muscle regeneration. Thus, Scrib is a regulator of tissue stem cells, controlling population expansion and self-renewal with Scrib expression dynamics directing satellite cell fate. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
    Cell Reports 02/2015; 10(7). DOI:10.1016/j.celrep.2015.01.045 · 8.36 Impact Factor
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    • "In the subcellular localization assay, mutations p.P1043L, p.P1332L and p.L1520R significantly altered the distribution of SCRIB subcellular localization, as more GFP-SCRIB localized to cytoplasmic instead of membrane domains. Previous structure–function analysis of human SCRIB indicated that both LRR and PDZ domains are required for correct localization [24,25]. In our study, one of the three functional mutations (p.P1043L) was located at the third PDZ domain. "
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    PLoS ONE 07/2013; 8(7):e69262. DOI:10.1371/journal.pone.0069262 · 3.23 Impact Factor
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    • "j o u r n a l h o m e p a g e : w w w. e l s e v i e r. c o m / l o c a t e / y v i r o plasma membrane-associated signal transducers appears to be of significance (reviewed in Pim and Banks, 2010). These proteins include Dlg, hScrib, MAGI and many others, and they are involved in activities such as tight junction assembly, the establishment of apicobasal polarity and cell cycle progression (Latorre et al., 2005; Nagasaka et al., 2006). The specificity for each of these PDZ domain-containing proteins depends on the particular E6 protein involved (Thomas et al., 2001), and on the localization and modification of the PDZ domain-containing proteins. "
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    ABSTRACT: The E6 protein from high-risk human papillomaviruses appears necessary for persistence of viral episomes in cells but the underlying mechanism is unclear. E6 has many activities, including its ability to bind and degrade PDZ domain-containing proteins, such as hScrib. However little is known about the role of these interactions for E6 function and the viral life cycle. We now show that the levels of expression of wild-type E6 are increased in the presence of hScrib whilst a mutant E6 protein lacking the PDZ-binding motif is found at lower levels as it is turned over more rapidly by the proteasome. This correlates with an inability of genomes containing this mutation to be maintained as episomes. These results show that E6 association with certain PDZ domain-containing proteins can stabilize the levels of E6 expression and provides one explanation as to how the PDZ-binding capacity of E6 might contribute to genome episomal maintenance.
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