# Lipid Droplet‐Localized Spindle Apparatus Coiled‐Coil Protein 1 Regulates Lipid Droplet Distribution

## TL;DR

This study identifies a protein that helps organize lipid droplets in cells by linking them to the microtubule network, influencing their distribution and cell division.

## Contribution

The paper discovers SPDL1-L as a novel lipid droplet-associated protein that regulates their transport and clustering via dynein.

## Key findings

- SPDL1-L localizes to lipid droplets through hydrophobic and basic residues.
- SPDL1-L promotes lipid droplet clustering at the microtubule-organizing center.
- SPDL1-L uses dynein to mediate minus end transport of lipid droplets.

## Abstract

Lipid droplets (LDs) are central to cellular energy homeostasis and lipid metabolism. While LD‐associated proteins are known to regulate LD dynamics and function, their roles in LD transport and their broader cellular significance remain poorly understood. In this study, we identify lipid droplet‐localized spindle apparatus coiled‐coil protein 1 (SPDL1‐L) as a key regulator of intracellular LD transport. SPDL1‐L localizes to LDs through the synergistic action of its hydrophobic region and nearby basic residues. SPDL1‐L expression promotes LD clustering at the microtubule‐organizing center (MTOC) and the formation of donut‐shaped (toroidal) nuclei during cell division. SPDL1‐L‐mediated LD clustering is likely through dynein‐mediated minus end transport. LD clustering activity is diminished when the LD targeting or dynein binding function of SPDL1‐L is impaired. Together, our findings provide new insights into the mechanisms governing LD dynamics and their impact on cellular organization.

SPDL1‐L, a long isoform of SPDL1, is identified as a bona fide lipid droplet‐associated protein that acts as a dynein adaptor to drive perinuclear clustering of lipid droplets. By linking lipid droplets to the microtubule network, SPDL1‐L extends the function of SPDL1 beyond mitosis and contributes to lipid droplet organization and nuclear remodeling.