Role for formin-like 1-dependent acto-myosin assembly in lipid droplet dynamics and lipid storage.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28361956.
- Also identified by DOI 10.1038/ncomms14858 and PMC identifier 5380971.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Lipid droplets (LDs) are cellular organelles specialized in triacylglycerol (TG) storage undergoing homotypic clustering and fusion. In non-adipocytic cells with numerous LDs this is balanced by poorly understood droplet dissociation mechanisms. We identify non-muscle myosin IIa (NMIIa/MYH-9) and formin-like 1 (FMNL1) in the LD proteome. NMIIa and actin filaments concentrate around LDs, and form transient foci between dissociating LDs. NMIIa depletion results in decreased LD dissociations, enlarged LDs, decreased hydrolysis and increased storage of TGs. FMNL1 is required for actin assembly on LDs in vitro and for NMIIa recruitment to LDs in cells. We propose a novel acto-myosin structure regulating lipid storage: FMNL1-dependent assembly of myosin II-functionalized actin filaments on LDs facilitates their dissociation, thereby affecting LD surface-to-volume ratio and enzyme accessibility to TGs. In neutrophilic leucocytes from MYH9-related disease patients NMIIa inclusions are accompanied by increased lipid storage in droplets, suggesting that NMIIa dysfunction may contribute to lipid imbalance in man.
Medical subject headings
- Actin Cytoskeleton
- Cytoskeletal Proteins
- Hearing Loss, Sensorineural
- Intracellular Signaling Peptides and Proteins
- Lipid Droplets
- Molecular Motor Proteins
- Myosin Heavy Chains
- Nonmuscle Myosin Type IIA
- Thrombocytopenia
- Triglycerides