I have evaluated this article for Faculty of 1000.
L Szpankowski, SE Encalada and LS Goldstein (2012) Subpixel colocalization reveals amyloid precursor protein-dependent kinesin-1 and dynein association with axonal vesicles. Proceedings of the National Academy of Sciences of the United States of America PMID: 22582169 DOI: 10.1073/pnas.1120510109
This paper caught my attention for the innovative image analysis approach as much as the core findings. The authors used accurate sub-pixel image analysis based on Gaussian fitting of pixel data, but instead of using this approach to define only the position of objects, they used this to define colocalization of components of vesicles moving along axons.
Much of their data is consistent with previous findings, but highlights several key features. First, that the Alzheimer’s amyloid precursor protein is required for the recruitment of both kinesin-1 and dynein motors to the vesicular carriers, second, that the ongoing presence of kinesin light chain 1 is required for recruitment of dynein. This observation is somewhat surprising and open to several interpretations – perhaps kinesin is required to drive recruitment of dynein, alternatively it might act to actively retain it once recruited. It is also possible that this finding reflects some sort of activity-dependent recruitment/retention of motors (i.e. that ongoing bidirectional motility is necessary). The methods are thoroughly described, and it is pleasing to see some clear critical analysis of the limitations of the approach used. This is a lengthy but worthwhile read, especially for anyone conducting similar work on the role of motors in organelle movement.
The original evaluation can be found at the F1000 site.