Lbr
Developmental stage
Strongly expressed in liver, skin, brain as well as in specific regions of the developing cartilage and bone in embryos.
Domain
The Tudor domain may not recognize methylation marks, but rather bind unassembled free histone H3.
Function
Catalyzes the reduction of the C14-unsaturated bond of lanosterol, as part of the metabolic pathway leading to cholesterol biosynthesis (PubMed:18785926). Plays a critical role in myeloid cell cholesterol biosynthesis which is essential to both myeloid cell growth and functional maturation (PubMed:22140257). Mediates the activation of NADPH oxidases, perhaps by maintaining critical levels of cholesterol required for membrane lipid raft formation during neutrophil differentiation (PubMed:22140257). Anchors the lamina and the heterochromatin to the inner nuclear membrane (By similarity).
Pathway
Steroid biosynthesis; cholesterol biosynthesis.
Post-translational modifications
Phosphorylated by CDK1 in mitosis when the inner nuclear membrane breaks down into vesicles that dissociate from the lamina and the chromatin (By similarity). It is phosphorylated by different protein kinases in interphase when the membrane is associated with these structures (By similarity). Phosphorylation of LBR and HP1 proteins may be responsible for some of the alterations in chromatin organization and nuclear structure which occur at various times during the cell cycle (By similarity). Phosphorylated by SRPK1 (By similarity). In late anaphase LBR is dephosphorylated, probably by PP1 and/or PP2A, allowing reassociation with chromatin (By similarity).
Sequence Similarities
Belongs to the ERG4/ERG24 family.
Tissue Specificity
Highly expressed in the testis and lung. Also expressed in the heart, ovary, kidney and liver.
Cellular localization
- Nucleus inner membrane
- Multi-pass membrane protein
- Nucleus
- Cytoplasm
- Endoplasmic reticulum membrane
- Nucleus; nuclear rim.
Alternative names
Delta(14)-sterol reductase LBR, Delta-14-SR, 3-beta-hydroxysterol Delta (14)-reductase, C-14 sterol reductase, Integral nuclear envelope inner membrane protein, Lamin-B receptor, Sterol C14-reductase, C14SR, Lbr