Putting organelles in their place

Abstract

Experiments in C. elegans reveal new insights into how the ANC-1 protein helps to anchor the nucleus and other organelles in place.

Keywords: C. elegans; ER; LINC complexes; cell biology; cellular organisation; nesprin; nuclear envelope; nuclear positioning.

Figure 1.. Loss of ANC-1 leads to unanchored and misshaped organelles and a smaller body size in worms.

The hypodermis of C. elegans worms (top schematic) is made up of hyp-7 cells which contain over a hundred nuclei (represented as black dots). In wild-type worms (left), the KASH protein ANC-1 (depicted as spikes) localizes to the membrane of the nucleus and endoplasmic reticulum (ER). As a result, the nuclei (purple) are spherical and evenly spaced, and the ER (blue), mitochondria (orange) and lipid droplets (yellow) are well anchored. The microtubule network (black lines) is also evenly distributed throughout the cytoplasm. Meanwhile, in mutant worms lacking the gene for ANC-1 (right), the ER and mitochondria are fragmented, and the nuclei are unanchored and clustered together. Lipid droplets are also clustered and the microtubule network is disrupted by the movement of the untethered organelles. This causes the mutant worm to have a smaller body size and the nuclei in its hyp-7 cells to be mispositioned.