Proper symmetric and asymmetric endoplasmic reticulum partitioning requires astral microtubules.
Mechanisms that regulate partitioning of the endoplasmic reticulum (ER) during cell division are largely unknown. Previous studies have mostly addressed ER partitioning in cultured cells, which may not recapitulate physiological processes that are critical in developing, intact tissues. We have addressed this by analysing ER partitioning in asymmetrically dividing stem cells, in which precise segregation of cellular components is essential for proper development and tissue architecture. We show that in Drosophila neural stem cells, called neuroblasts, the ER asymmetrically partitioned to centrosomes early in mitosis. This correlated closely with the asymmetric nucleation of astral microtubules (MTs) by centrosomes, suggesting that astral MT association may be required for ER partitioning by centrosomes. Consistent with this, the ER also associated with astral MTs in meiotic Drosophila spermatocytes and during syncytial embryonic divisions. Disruption of centrosomes in each of these cell types led to improper ER partitioning, demonstrating the critical role for centrosomes and associated astral MTs in this process. Importantly, we show that the ER also associated with astral MTs in cultured human cells, suggesting that this centrosome/astral MT-based partitioning mechanism is conserved across animal species.
Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences-F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA.
Jeremy T
JT
Smyth
Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
Todd A
TA
Schoborg
Department of Biology, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, USA.
Zane J
ZJ
Bergman
Department of Biology, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, USA.
Blake
B
Riggs
Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA nasser@nih.gov.
Nasser M
NM
Rusan
D000818:Animals; D002455:Cell Division; D002460:Cell Line; D004330:Drosophila; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008297:Male; D008870:Microtubules / Q000378:metabolism*; D008938:Mitosis / Q000502:physiology; D013090:Spermatocytes / Q000502:physiology; D008941:Spindle Apparatus
Drosophila; asymmetric division; centrosome; endoplasmic reticulum; mitosis