Modification of the erythroid transcription factor GATA-1 by SUMO-1
- Licio Collavin*,†,‡,
- Monica Gostissa*,‡,
- Fabio Avolio§,
- Paola Secco§,
- Antonella Ronchi¶,
- Claudio Santoro§,∥, and
- Giannino Del Sal*,†
- *Laboratorio Nazionale Consorzio Interuniversitario Biotecnologie, AREA Science Park, Padriciano 99, 34012 Trieste, Italy; †Dipartimento di Biochimica, Biofisica e Chimica delle Macromolecole, Università degli Studi di Trieste, Via L. Giorgeri 1, 34129 Trieste, Italy; §Dipartimento di Scienze Mediche, Università del Piemonte Orientale “A. Avogadro,” Via Solaroli 17, 28100 Novara, Italy; and ¶Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, 20126 Milano, Italy
-
Edited by Robert Tjian, University of California, Berkeley, CA, and approved April 27, 2004 (received for review December 23, 2003)
Abstract
The activity of transcription factors is tightly modulated by posttranslational modifications affecting stability, localization, and protein–protein interactions. Conjugation to SUMO is a reversible posttranslational modification that has been shown to regulate important transcription factors involved in cell proliferation, differentiation, and tumor suppression. Here, we demonstrate that the erythroid transcription factor GATA-1 is sumoylated in vitro and in vivo and map the single lysine residue involved in SUMO-1 attachment. We show that the nuclear RING finger protein PIASy promotes sumoylation of GATA-1 and dramatically represses its transcriptional activity. We present evidence that a nonsumoylatable GATA-1 mutant is indistinguishable from the WT protein in its ability to transactivate a reporter gene in mammalian cells and in its ability to trigger endogenous globin expression in Xenopus explants. These observations open interesting questions about the biological role of this posttranslational modification of GATA-1.
