The lamin B receptor of the inner nuclear membrane undergoes mitosis-specific phosphorylation and is a substrate for p34cdc2-type protein kinase
| Autor: | J C, Courvalin, N, Segil, G, Blobel, H J, Worman |
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| Rok vydání: | 1992 |
| Předmět: |
Lamin Type B
Nuclear Envelope Recombinant Fusion Proteins Molecular Sequence Data Mitosis Nuclear Proteins Receptors Cytoplasmic and Nuclear Receptors Cell Surface In Vitro Techniques Phosphoproteins Peptide Mapping Lamins Phosphothreonine CDC2 Protein Kinase Consensus Sequence Animals Amino Acid Sequence Phosphorylation Chickens Cells Cultured |
| Zdroj: | The Journal of biological chemistry. 267(27) |
| ISSN: | 0021-9258 |
| Popis: | The lamin B receptor (LBR) is an integral protein of the inner nuclear membrane that interacts with lamin B in vitro. If contains a 204-amino acid nucleoplasmic amino-terminal domain and a hydrophobic carboxyl-terminal domain with eight putative transmembrane segments. We found cell cycle-dependent phosphorylation of LBR using phosphoamino acid analysis and phosphopeptide mapping of in vivo 32P-labeled LBR immunoprecipitated from chicken cells in interphase and arrested in mitosis. LBR was phosphorylated only on serine residues in interphase and on serine and threonine residues in mitosis. Some serine residues phosphorylated in interphase were not phosphorylated in mitosis. To identify a threonine residue specifically phosphorylated in mitosis and the responsible protein kinase, wild-type and mutant LBR nucleoplasmic domain fusion proteins were phosphorylated in vitro by p34cdc2-type protein kinase. Comparisons of phosphopeptide maps to those of in vivo 32P-labeled mitotic LBR showed that Thr188 is likely to be phosphorylated by this enzyme during mitosis. These phosphorylation/dephosphorylation events may be responsible for some of the changes in the interaction between the nuclear lamina and the inner nuclear membrane that occur during mitosis. |
| Databáze: | OpenAIRE |
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