CIDEA
Domain
The amphipathic helix mediates embedding into the lipid droplet phospholipid monolayer, promoting phosphatidic acid-binding, thereby facilitating triacylglycerol transfer.
The CIDE-N domain is involved in homodimerization which is crucial for its function in promoting lipid exchange and transfer.
Function
Lipid transferase that promotes unilocular lipid droplet formation by mediating lipid droplet fusion (PubMed:19843876, PubMed:26118629). Lipid droplet fusion promotes their enlargement, restricting lipolysis and favoring lipid storage (PubMed:19843876). Localizes on the lipid droplet surface, at focal contact sites between lipid droplets, and mediates atypical lipid droplet fusion by promoting directional net neutral lipid transfer from the smaller to larger lipid droplets (By similarity). The transfer direction may be driven by the internal pressure difference between the contacting lipid droplet pair and occurs at a lower rate than that promoted by CIDEC (By similarity). May also act as a CEBPB coactivator in epithelial cells to control the expression of a subset of CEBPB downstream target genes, including ID2, IGF1, PRLR, SOCS1, SOCS3, XDH, but not casein (By similarity). By interacting with CEBPB, strengthens the association of CEBPB with the XDH promoter, increases histone acetylation and dissociates HDAC1 from the promoter (By similarity). When overexpressed, induces apoptosis; the physiological significance of its role in apoptosis is unclear (By similarity).
Involvement in disease
In omental and subcutaneous adipose tissue of obese patients matched for BMI, expression levels correlate with insulin sensitivity. Expression is increased 5-6 fold in the group of patients with high insulin sensitivity, compared to the insulin-resistant group. This observation is consistent with the idea that triglyceride storage in adipocytes plays an important role in sequestering triglycerides and fatty acids away from the circulation and peripheral tissues, thus enhancing insulin sensitivity in liver and muscle.
Sequence Similarities
Belongs to the CIDE family.
Tissue Specificity
Expressed in omental and subcutaneous adipose tissue (at protein level).
Cellular localization
- Lipid droplet
- Nucleus
- Enriched at lipid droplet contact sites.
Alternative names
Lipid transferase CIDEA, Cell death activator CIDE-A, Cell death-inducing DFFA-like effector A, CIDEA