Format

Send to

Choose Destination
Curr Biol. 2003 Sep 30;13(19):1660-8.

A determinant for directionality of organelle transport in Drosophila embryos.

Author information

1
Department of Developmental and Cell Biology, 2222 Natural Sciences I, University of California-Irvine, Irvine, CA 92697, USA.

Abstract

BACKGROUND:

Motor-driven transport along microtubules is a primary cellular mechanism for moving and positioning organelles. Many cargoes move bidirectionally by using both minus and plus end-directed motors. How such cargoes undergo controlled net transport is unresolved.

RESULTS:

Using a combination of genetics, molecular biology, and biophysics, we have identified Halo, a novel regulator of lipid droplet transport in early Drosophila embryos. In embryos lacking Halo, net transport of lipid droplets, but not that of other cargoes, is specifically altered; net transport is minus-end directed at developmental stages when it is normally plus-end directed. This reversal is due to an altered balance of motion at the level of individual organelles; without Halo, travel distances and stall forces are reduced for plus-end and increased for minus-end motion. During development, halo mRNA is highly upregulated just as net plus-end transport is initiated (phase II), and its levels drop precipitously shortly before transport becomes minus-end directed (phase III). Exogenously provided Halo prevents the switch to net minus-end transport in phase III in wild-type embryos and induces net plus-end transport during phase II in halo mutant embryos. This mechanism of regulation is likely to be of general importance because the Drosophila genome encodes a family of related proteins with similar sequences, each transiently expressed in distinct domains.

CONCLUSIONS:

We conclude that Halo acts as a directionality determinant for embryonic droplet transport and is the first member of a new class of transport regulators.

PMID:
14521831
DOI:
10.1016/j.cub.2003.08.032
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center