Work

Regulation of Protein Arginine Methyltransferase 8 (PRMT8) Activity by Its N-terminal Domain

Year: 2007

Type: article

Abstract: Human protein arginine methyltransferase PRMT8 has been recently described as a type I enzyme in brain that is localized to the plasma membrane by N-terminal myristoylation. The amino acid sequence of human PRMT8 is almost 80% identical to human PRMT1, the major protein arginine methyltransferase activity in mammalian cells. However, the activity of a recombinant PRMT8 GST fusion protein toward methyl-accepting substrates is much lower than that of a GST fusion of PRMT1. We show here that both His-tagged and GST fusion species lacking the initial 60 amino acid residues of PRMT8 have enhanced enzymatic activity, suggesting that the N-terminal domain may regulate PRMT8 activity. This conclusion is supported by limited proteolysis experiments showing an increase in the activity of the digested full-length protein, consistent with the loss of the N-terminal domain. In contrast, the activity of the N-terminal truncated protein was slightly diminished by limited proteolysis. Significantly, we detect automethylation at two sites in the N-terminal domain, as well as binding sites for SH3 domain-containing proteins. We suggest that the N-terminal domain may function as an autoregulator that may be displaced by interaction with one or more physiological inducers.

Source: Journal of Biological Chemistry

DOI: 10.1074/jbc.m704650200

Authors: Joyce Sayegh, Kristofor Webb, Donghang Cheng, Mark T. Bedford, Steven G. Clarke

Institutions: University of California, Los Angeles, The University of Texas MD Anderson Cancer Center

Language: English

Topic: Cancer-related gene regulation

Subfield: Molecular Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: hybrid

Estimated APC paid: $3,430

Funder: National Institute of General Medical Sciences