Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents

This Article Full Text (PDF, 2428K) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by LeBrasseur, N. Search for Related Content PubMed Articles by LeBrasseur, N. Social Bookmarking                            What's this?

BARS takes Golgi apart

Golgi fragmentation (top) at mitosis is blocked if BARS is depleted (bottom). Corda/AAAS

Cristina Hidalgo Carcedo, Alberto Luini, Daniela Corda, and colleagues (Consorzio Mario Negri Sud, Santa Maria Imbaro, Italy) suggest that Golgi membranes are chopped up by a protein called BARS before mitosis can occur. Their cell culture studies contrast, however, with results from genetic knock-out experiments.

BARS is closely related to the CtBP family of transcriptional repressors needed for normal embryonic development in mouse and fly. Corda and Luini previously found that, in rat cells, BARS is what brefeldin A might target with its ADP ribosylation activity when it inhibits Golgi trafficking. Their subsequent work suggested that BARS is needed for the fission of vesicles during trafficking.

The new report indicates that BARS also cuts up the Golgi into vesicles and small tubules to be shared by daughter cells. The authors removed BARS activity from cultured rat cells using antisense methods or from an in vitro Golgi fission assay by immunodepletion or dominant-negative mutants. In all cases, Golgi stacks disassembled into a tubular network, but were not fragmented further into vesicles. The BARS-depleted cells did not enter mitosis, a known side effect of the failure to break down the Golgi.

How BARS might induce fission is unclear. Its acyl transferase activity modifies lipids such as LPA and might thus induce a needed structural change in the membrane. However, mutation of this activity reduced but did not abolish its fission activity in vitro.

Mice CtBP mutants have developmental problems, but cell cultures can be made from these lines, and architectural Golgi defects have not yet been found. "We think that BARS is the main mechanism for Golgi fission during mitosis," says Corda, "and that there are other redundant mechanisms that can take over where BARS fails." Fail-safes might include dynamin, which has also been proposed to cleave the Golgi.

Reference:

Hidalgo Carcedo, C., et al. 2004. Science. 305:93–96.[Abstract/Free Full Text]

Nicole LeBrasseur

lebrasn{at}rockefeller.edu

CiteULike    Complore    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?

This Article Full Text (PDF, 2428K) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by LeBrasseur, N. Search for Related Content PubMed Articles by LeBrasseur, N. Social Bookmarking                            What's this?