This new Special Issue of FEBS Letters, guest-edited by Maria Bohnert (University of Münster) and Bianca Schrul (Saarland University), provides an overview of lipid droplet functions in physiological and pathological states. Sixteen reviews highlight recent discoveries concerning the lipid droplet life cycle, technological advances in the lipid droplet field, and insights into the cell biology underlying diseases related to lipid storage.

The Special Issue includes diverse Reviews on lipid droplet form and function, exploring the lipid droplet lipidome [1], growth and fusion [2], communication with other cellular organelles [3][4][5], lipolysis [6][7], seipin and its partner proteins [8], and triacylglycerol synthesis [9].

Three Reviews highlight technical and technological advancements in understanding lipid droplet form, transport, and biogenesis, including the contributions of electron microscopy [10], a new enzymatic mass tagging method [11], and molecular dynamics simulations [12].

Other Reviews explore the roles of lipid droplets and associated proteins in pathological states, including lipotoxcity and lipid overload [13], and cancer cell metabolism [14]. The Special Issue also features two new Graphical Reviews depicting roles of lipid droplets in disease: one concerning viral replication [15], and another concerning inherited human disorders [16].  

FEBS Letters thanks the guest editors for their input and dedication in curating the publication of this excellent issue, and we invite you to read their full editorial. We believe this Special Issue will be of great interest to the community of scientists "currently dissecting the molecular basis of the (patho-) physiological lipid droplet life cycle in a collective effort".

1. Wölk M and Federova M (2024) The lipid droplet lipidome. FEBS Lett 598, 1215–1225. 
2. Xu L, Li L, Wu L, Li P and Chen FJ (2024) CIDE proteins and their regulatory mechanisms in lipid droplet fusion and growth. FEBS Lett 598, 1154–1169. 
3. Enkler L and Spang A (2024) Functional interplay of lipid droplets and mitochondria. FEBS Lett 598, 1235–1251. 
4. Monteiro-Cardoso VF and Giordano D (2024) Emerging functions of the mitochondria–ER–lipid droplet three-way junction in coordinating lipid transfer, metabolism, and storage in cells. FEBS Lett 598, 1252–1273. 
5. Saukko-Paavola AJ and Klemm RW (2024) Remodelling of mitochondrial function by import of specific lipids at multiple membrane-contact sites. FEBS Lett 598, 1274–1291. 
6. Griseti E, Bello AA, Bieth E, Sabbagh B, Iacovoni JS, Bigay J, Laurell H and Copic A (2024) Molecular mechanisms of perilipin protein function in lipid droplet metabolism. FEBS Lett 598, 1170–1198. 
7. Henne WM (2024) Molecular determinants of lipid droplet subpopulations and their fates. FEBS Lett 598, 1199–1204. 
8. Klug YA, Ferreira JV and Carvalho P (2024) A unifying mechanism for seipin-mediated lipid droplet formation. FEBS Lett 598, 1116–1126. 
9. Barbosa AD and Siniossoglou S (2024) Membranes that make fat: roles of membrane lipids as acyl donors for triglyceride synthesis and organelle function. FEBS Lett 598, 1226–1234. 
10. Dudka W, Salo VT and Mahamid J (2024) Zooming into lipid droplet biology through the lens of electron microscopy. FEBS Lett 598, 1127–1142. 
11. John Peter AT and Kornmann B (2024) Uncovering mechanisms of interorganelle lipid transport by enzymatic mass tagging. FEBS Lett 598, 1292–1298. 
12. Sapia J and Vanni S (2024) Molecular dynamics simulations of intracellular lipid droplets: a new tool in the toolbox. FEBS Lett 598, 1143–1153. 
13. Obaseki E, Adebayo D, Bandyopadhyay S and Hariri H (2024) Lipid droplets and fatty acid-induced lipotoxicity: in a nutshell. FEBS Lett 598, 1207–1214. 
14. Safi R, Menendez P and Pol A (2024) Lipid droplets provide metabolic flexibility for cancer progression. FEBS Lett 598, 1301–1327. 
15. Herker E (2024) Lipid droplets in virus replication. FEBS Lett 598, 1299–1300. 
16. Duan X and Savage DB (2024) The role of lipid droplet associated proteins in inherited human disorders. FEBS Lett 598, 1205–1206.