Detection of exocytosis from TIRFM image sequences. Spatial-temporal analysis of fusions maps
Exocytosis is an essential cellular trafficking process integral
to the proper distribution and function of a plethora of molecules
including transporters, receptors and enzymes. Moreover,
incorrect protein targeting can lead to pathological conditions.
Recently, the application of evanescent wave microscopy has
allowed us to image the final steps of exocytosis. However,
spatio-temporal analysis of fusion of constitutive vesicular
traffic with the plasma membrane has not been systematically
performed. Also the spatial sites and times of vesicle fusion have
not yet been analyzed together.
In addition, more formal tests are
required in testing biological hypotheses, rather than visual
inspection combined with statistical descriptives. We use the spatial Ripley
K-functions to examine the joint and marginal behavior of locations
and fusion times. We have developped a semi-automatic process for
detection and mapping of constitutive fusion sites. It allowed us
to reveal spatial and temporal clustering, but no dependency between
the locations and times of fusion events. Our novel approach could be translated to other studies of membrane trafficking in health and
diseases such as diabetes.
Software
Publications
- Sebastian R, Díaz ME, Ayala G, Letinic K, Moncho-Bogani J, Toomre D. Spatio-Temporal Analysis of Constitutive Exocytosis in Epithelial Cells. IEEE/ACM Transactions on Computational Biology and Bioinformatics. 3(1):17-32, 2006
- Keller P, Toomre D, Díaz ME, White J, Simons K. Multicolour Imaging of post-Golgi Sorting and Trafficking in Live Cells. Nature Cell Biology. 3(2):140-49, 2001
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