March 11, 2010

When chromosomes are not segregated correctly during mitosis, the resulting cells have an abnormal number of chromosomes, a hallmark of many tumors. The above image shows DNA (blue) with a single chromosomal locus tagged (green) in different stages of a cell division with proper chromosome segregation. Image is part of a new paper showing that the p53 tumor suppressor pathway functions to limit human cell growth after chromosome missegregation.

Reference: Sarah L . Thompson and Duane A. Compton, 2010. Originally published in Journal of Cell Biology, doi 10.1083/jcb.200905057. Paper can be found here.

March 8, 2010

Mutations in the genes PINK1 and Parkin lead to a form of Parkinsons disease. Both PINK1 and Parkin function in protecting cells from damaged mitochondria, and a recent study helps clear up how. PINK1 accumulates on damaged mitochondria, which in turn recruits Parkin to trigger their elimination. Image shows Parkin (left) can be recruited to distressed and depolarized mitochondria (middle) in the presence of PINK1. Box on right shows an enlarged overlay of Parkin and miotchondria.

Reference: Derek P. Narendra, Seok Min Jin, Atsushi Tanaka, Der-Fen Suen, Clement A. Gautier, Jie Shen, Mark R. Cookson, Richard J. Youle. Authors’ PLoS Biology paper can be found here.

March 4, 2010

Microtubules are important cytoskeletal structures that can be modified in ways that allow for specific cellular functions. Kinesins are microtubule motors, and a recent study has tested how different kinesins move along microtubules modified in different ways. For example, one kinesin will only walk along stable microtubules, while two other kinesin motors are not so selective. The image above shows a Kinesin-2 family member (left) moving along all microtubule tracks (middle) in a cell.

Reference: Dawen Cai, Dyke P. McEwen, Jeffery R. Martens, Edgar Meyhofer, Kristen J. Verhey. Their PLoS Biology paper can be found here.

March 1, 2010

Myosin is an actin-based molecular motor that functions in many cellular processes. A novel myosin (Myo19) is associated with mitochondrial, and functions in the movement and dynamics of the mitochondrial network. The image shows a cultured cell with this novel myosin (yellow), actin (purple), and DNA (white).

Reference: Quintero OA, DiVito MM, Adikes RC, Kortan MB, Case LB, Lier AJ, Panaretos NS, Slater SQ, Rengarajan M, Feliu M, Cheney RE

Paper and similar images found in the authors’ Current Biology paper here.

February 25, 2010

Networks of actin filaments can provide force within a cell to generate movement, but the mechanism of how this occurs isn’t completely understood. A group recently created a computer model to simulate and predict motility caused by actin polymerization, and tested new predictions experimentally. The figure above shows how an actin network uniformly coating a bead will break its symmetry to result in movement of the bead (top). The computer simulation (middle) and a 3D view of the simulation (bottom) are also shown.

Reference:

Mark J. Dayel, Orkun Akin, Mark Landeryou, Viviana Risca, Alex Mogilner, R. Dyche Mullins. Article found here.