Golgi's function stretches it thin: molecules may explain odd shape of cell's trafficking hub.
Researchers have pinpointed a protein that keeps trains running through the cell's Grand Central station.
The protein works with other molecules to pull membrane packets off the surface of the Golgi apparatus, giving the organelle its distinctive flattened shape.
"It's a nice simple mechanism for how the shape of something is a consequence of its function," says Seth Field of the University of California, San Diego and a coauthor of the study in the Oct. 16 Cell.
The Golgi apparatus is a well known staging area for all proteins that leave the cell, including hormones, antibodies and components of hair, bone and skin. But the Golgi's odd shape has long been a mystery. Researchers have described it as a stack of pancakes, each enclosing empty space that proteins travel through.
In an analysis of the binding properties of about 4,000 fruit fly proteins, researchers found that one called GOLPH3 latched onto another molecule important to Golgi function.
Further scans found that a motor protein like those found in muscles piggybacked on GOLPH3. If any one of the molecules--GOLPH3, the molecule attached to it or the motor protein--was removed, the Golgi structure collapsed and shut down.
The team concluded that the Golgi's shape is a side effect of its job. The motor protein enables GOLPH3 to pull bubbles of proteins off the Golgi apparatus and send them out of the cell. In the process, the membranes are pulled flat like rubber bands.
Linking the three molecules "ties together a lot of things that people have suspected but couldn't quite put their hands on," says Helen Yin of the University of Texas Southwestern Medical Center at Dallas.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||Genes & Cells|
|Article Type:||Brief article|
|Date:||Nov 7, 2009|
|Previous Article:||New view of genome reveals how cell packs DNA neatly into place: model of 3-D structure shows that fractal folding is key.|
|Next Article:||Monkey moms have their own kind of baby talk: macaques smack their lips to exchange emotional cues.|