Exp Mol Med.  2005 Jun;37(3):155-160.

Increased lysine N-methylation of a 23-kDa protein during hepatic regeneration

• Choi YB
• Ko MH
• Shin CH
• Kim KS
• Hong KM
• Paik MK
• Park DE

Abstract

The methylation of a 23-kDa nuclear protein increased after partial hepatectomy and methylation returned to basal levels after the initial stage of regeneration. The methylating enzyme was partially purified from rat liver by ammonium sulfate precipitation, DEAE-anion exchange chromatography and Butyl-Sepharose chromatography. The 23-kDa protein was purified from a nuclear fraction of liver tissue with SP-Sepharose. When the 23-kDa protein was methylated with the partially purified methyltransferase and analyzed on C18 high performance liquid chromatography (HPLC), the methylated acceptor amino acid was monomethyl lysine (MML). Previously, only arginine N-methylation of specific substrate proteins has been reported during liver regeneration. However, in this report, we found that lysine N-methylation increased during early hepatic regeneration, suggesting that lysine N-methylation of the 23-kDa nuclear protein may play a functional role in hepatic regeneration. The methyltransferase did not methylate other proteins such as histones, hnRNPA1, or cytochrome C, suggesting the enzyme is a 23-kDa nuclear protein- specific lysine N-methyltransferase.

Keyword

lysine N-methylation; lysine N-methyltransferase; methylated amino acid analysis; nuclear 23- kDa protein; regenerating rat liver

MeSH Terms

Animals
Cytochromes c/metabolism
DNA Helicases/metabolism
Hepatectomy
Histone-Lysine N-Methyltransferase/*metabolism
Histones/metabolism
Liver
Liver Regeneration/*physiology
Lysine/*metabolism
Methylation
Proteins/*metabolism
Rats
Rats, Sprague-Dawley
Research Support, Non-U.S. Gov't