Changes in localization of human discs large (hDlg) during keratinocyte differentiation is associated with expression of alternatively spliced hDlg variants
- Cancer Research UK Institute for Cancer Studies, University of Birmingham, Vincent Drive, Edgbaston, Birmingham B15 2TT (United Kingdom)
- Molecular Biotechnology Center, University of Turin, Via Nizza 52, 10126 Torino (Italy)
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138 (United States)
- Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, MA 02129 (United States)
Alternative spliced variants of the human discs large (hDlg) tumour suppressor are characterized by combinations of insertions. Here, using insertions I2- and I3-specific antibodies, we show that I2 and I3 variants have distinct distributions in epidermal and cervical epithelia. In skin and cervix, I3 variants are found in the cytoplasm. Cytoplasmic localization of I3 variants decreases as cervical keratinocytes differentiate, concomitant with relocalization to the cell periphery. I2 variants are found at the cell periphery of differentiated epidermal and cervical keratinocytes. Nuclear localization of I2 variants was evident in both tissues, with concentration of nuclear I2 variants in basal and parabasal cervical keratinocytes. A prominent nuclear localization of hDlg in cells of hyperproliferative layers of psoriatic lesions, but not in mature differentiated keratinocytes, together with I2 redistribution in differentiating keratinocytes, suggests that nuclear hDlg functions may be pertinent to growth of undifferentiated cells. Supporting our findings in squamous tissues, a decrease of nuclear hDlg and an increase of membrane-bound and cytoplasmic hDlg upon calcium-induced keratinocyte differentiation were not concomitant processes. Furthermore, we confirm that the exit of I2 variants from the nucleus is linked to stimulation of epithelial differentiation. The dynamic redistribution of hDlg also correlated with a marked increase in the expression of I3 variants while the level of I2 variants showed only a moderate decrease. Because changes in the intracellular distribution of hDlg splice variants, and in their expression levels, correlate with changes in differentiation state we hypothesize that the different hDlg isoforms play distinct roles at various stages of epithelial differentiation.
- OSTI ID:
- 20972079
- Journal Information:
- Experimental Cell Research, Vol. 313, Issue 12; Other Information: DOI: 10.1016/j.yexcr.2007.05.017; PII: S0014-4827(07)00245-5; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0014-4827
- Country of Publication:
- United States
- Language:
- English
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