Identification of lamin B2 as a substrate of protein kinase C in BALB/MK-2 mouse keratinocytes

J Biol Chem. 1991 Oct 25;266(30):20018-23.

Abstract

Protein phosphorylation by activation of protein kinase C was examined using quiescent cultures of the mouse epidermal keratinocyte line BALB/MK-2. Treatment with phorbol ester caused rapid phosphorylation of five proteins with molecular weights of 80,000, 70,000, 40,000, 34,000, 28,000. Of these proteins, the 70,000 molecular weight one (p70) was studied further. Its position on two-dimensional gel suggested that p70 is nuclear envelope lamin B. This possibility was confirmed by the co-migration of p70 with the lamin fraction of mouse liver and its immunoprecipitation with antinuclear lamina antibody. The lamin B fraction consists of lamin B1 and lamin B2. Evidence that p70 is lamin B2 was obtained by peptide mapping and amino acid sequencing. Lamin B2 is the only lamin that shows a substantial increase in phosphorylation on treatment of BALB/MK-2 cells with phorbol ester.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell-Free System
  • Electrophoresis, Gel, Two-Dimensional
  • Keratinocytes / enzymology*
  • Lamin Type B
  • Lamins
  • Mice
  • Mice, Inbred BALB C
  • Molecular Sequence Data
  • Nuclear Proteins / metabolism*
  • Peptide Mapping
  • Phosphorylation
  • Precipitin Tests
  • Protein Kinase C / metabolism*
  • Sequence Homology, Nucleic Acid
  • Substrate Specificity

Substances

  • Lamin Type B
  • Lamins
  • Nuclear Proteins
  • Protein Kinase C