Covalent modification of the homeodomain-interacting protein kinase 2 (HIPK2) by the ubiquitin-like protein SUMO-1.
Posttranslational modifications such as ubiquitination and phosphorylation play an important role in the regulation of cellular protein function. Homeodomain-interacting protein kinase 2 (HIPK2) is a member of the recently identified family of nuclear protein kinases that act as corepressors for homeodomain transcription factors. Here, we show that HIPK2 is regulated by a ubiquitin-like protein, SUMO-1. We demonstrate that HIPK2 localizes to nuclear speckles (dots) by means of a speckle-retention signal. This speckle-retention signal contains a domain that interacts with a mouse ubiquitin-like protein conjugating (E2) enzyme, mUBC9. In cultured cells, HIPK2 is covalently modified by SUMO-1, and the SUMO-1 modification of HIPK2 correlates with its localization to nuclear speckles (dots). Thus, our results provide firm evidence that the nuclear protein kinase HIPK2 can be covalently modified by SUMO-1, which directs its localization to nuclear speckles (dots).
Pubmed ID: 10535925
Proceedings of the National Academy of Sciences of the United States of America
October 26, 1999
- Amino Acid Sequence
- Base Sequence
- Carrier Proteins
- Cell Line
- DNA Primers
- Molecular Sequence Data
- Protein Kinases
- Protein-Serine-Threonine Kinases
- SUMO-1 Protein
- Sequence Homology, Amino Acid
- Ubiquitin-Conjugating Enzymes