Table 1.
Proteins on human macrophage foam cell lipid droplets (LDs)
| Protein | Function | Protein | Function |
|---|---|---|---|
| Cholesterol Efflux | |||
| CORO1A | Phagolysosome assembly and maturation | DSC1 | Regulates apoAI-medidated cholesterol efflux |
| LAMTOR5 | Lysosomal Ragulator complex/metabolic signaling | PSAP | Regulates cathepsin B/D activity, lipid trafficking and autophagy |
| PARK7 | Positively regulates autophagy | Lipid transport | |
| VDAC2 | Macroautophagy suppressor | FABP4 | Fatty acid transport protein |
| YWHAZ | 14-3-3 protein zeta/delta | FABP5 | Fatty acid transport protein |
| YWHAG | 14-3-3 protein gamma | PPIA | Regulates lipid droplet size |
| YWHAE | 14-3-3 protein epsilon | GOT2 | Facilitates cellular uptake of long-chain free fatty acids |
| YWHAQ | 14-3-3 protein theta | Lysosomal function | |
| DAP | Negatively regulates autophagy | CTSB,D,L,S | Lysosomal cysteine proteases with roles in autophagy vescicle trafficking |
| HMGB1 | Novel BECN1 interacting partner, promotes autophagy | SLC25A5 | Lysosomal solute carrier transporters implicated in autophagy/phagocytosis |
| SLC25A6 | Lysosomal solute carrier transporters implicated in autophagy/phagocytosis | ||
| TBCs | Autophagy and protein aggregation | MYL6 | Myosin proteins linking autophagy receptors to autophagosomes |
| EEF1A1 | Regulation of chaperone-mediated autophagy | MYH6,7,9 | Myosins |
| GRPEL1 | Co-chaperone | MYL12A,B | Light chain myosin |
| HSP90AA1 | Chaperone-mediated autophagy | NPC2 | Autophagy-lysosomal activity, mitophagy and lipid efflux from lysosomes |
| HSP90AB1 | Molecular chaperone | SCARB2 | Lysosomal membrane protein, autophagy-lysosome pathway |
| HSP90B1 | HSP90 paralogue, regulates innate and adaptive immunity | Neutral lipases | |
| HSPA8 | Chaperone-mediated autophagy, autophagy and exocytosis | CES1 | Cholesterol ester hydrolase |
| HSPA9 | Mitochondrial chaperone | PNPLA2 | Patatin-like phospholipase domain-containing protein 2 |
| HSPB1 | Regulation of autophagy | LDAH | Lipid droplet-associated hydrolase |
| HSPD1 | Chaperonin | FAF2 | Inhibits PLPL2 |
| HSPE1 | Chaperonin | Rab proteins | |
| HSPH1 | Co-regulator of chaperone function | RAB1A | Regulation of autophagosome assembly |
| HYOU1 | Hypoxia-regulated chaperone | RAB2A | Promotes autopahgy |
| P4HB | ER chaperone | RAB5C | Member of the Ras-related protein family |
| PDIA3 | ER chaperone | RAB6A | Regulates autophagy, binds to Atg8 family members |
| PDIA4 | ER chaperone | RAB6B | Regulates autophagy, binds to Atg8 family members |
| TCP1 | Chaperonin | RAB7A | Regulates lipophagy by mediating recruitement of lysosome to the LD |
| HSPA5 | N-end rule proteolytic pathway, autophagy degradation | RAB10 | Required for LC3 recruitment ot autophagosomes |
| RAB11A | Regulates endosomal cholesterol movement to lipid droplets | ||
| H2A | Core histone | RAB11B | Regulates endosomal cholesterol movement to lipid droplets |
| H2B | Core histone | RAB14 | Phagolysosome assembly |
| H3 | Core histone | RAB18 | Promotes LD growth and autophasosome formation |
| H4 | Core histone | RAB21 | Promotes lipid droplet growth and autophasosome formation |
| Stress granule regulation | |||
| PLIN2 | Lipid droplet coat protein, intermediate-sized lipid droplets | FUS | Stress granule assembly factor |
| PLIN3 | Lipid droplet coat protein, small lipid droplets | PABPN1,C4 | mRNA translation regulators |
| VIM | Cytoskeletal protein | Cellular Traficking | |
| COPB2 | Golgi coatamer complex, delivery of PLIN2 to lipid droplets | ||
| ACADM | Fatty acid oxidation | CLTC | Vesicle coat protein, intracellular trafficking and endocytosis |
| ACADVL | Fatty acid oxidation | ANXA2 | Calcium dependent membrane protein involved in exocytosis |
| ACSL3 | Fatty acid oxidation | CHMP4B | Part of the ESCRT machinery |
| ACSL4 | Fatty acid oxidation | Ubiquitination machinery | |
| ALDH9A1 | Aldehyde dehydrogenase | AUP1 | Ubiquitin binding, UBE2G2 |
| ASAH1 | Lysosomal ceramidase | RPS27A | Monoubiquitin |
| CS | Citrate synthase | UBB, UBC | Polyubiquitin |
| CYB5R3 | Desaturation and elongation of fatty acids, cholesterol synthesis | UBA52 | Monoubiquitin |
| DLD | Lipoamide dehydrogenase | VCP | Aggresome assembly, autophagosome maturation |
| DLST | Mitochondrial succinyltransferase | Others | |
| GANAB | Catalytic subunit of glucosidase II | ALDOA | Fructose-biphosphate aldolase |
| HSD17B11 | Short-chain alcohol dehydrogenase | ARHGDIA | Rho GDP-dissociation inhibitor |
| LSS | Lanosterol synthase | ARHGDIB | Rho GDP-dissociation inhibitor |
| MAN2B1 | Alpha-mannosidase, lysososmal oligosaccharide degradation | CDC42 | GTPase |
| MDH2 | Malate dehydrogenase | GAPDH | Converts D-glyceraldehyde 3-phosphate to 3-phospho-D-glyceroyl phosphate |
| METTL7A | Methyltransferase | GNB1 | GTPase |
| PLA2G4C | Phospholipase involved in lipid droplet biogenesis | LDHA | Converts pyruvate into lactate |
| RHOA,C | Regulation of lipases | RAC2 | GTPase |
| SDHA | Mitochondrial electron transport chain, Complex II | RAP1A | GTPase |
| SUCLG1 | Hydrolyses succinyl-CoA | TPD52L2 | Promotes neutral lipid storage, contains a 14-3-3 binding motif |
| UQCRC1 | Component of the ubiquinol-cytochrome c reductase complex | VAPA | Localized to membrane contact sites |
LDs were purified from agLDL-loaded THP-1 macrophages by density gradient centrifugation and subjected to mass spectrometry. Names and cell function of identified proteins are shown.