The structure of the cascade reflects the fact that within any single image, the overwhelming majority of sub-windows are negative [11].
The structure of the cascade detector (introduced in face detection by Viola and Jones [1]) is that of a degenerated decision tree.
The optimal estimators have the structure of the cascade of a discrete linear time-invariant smoother and a generalized hold, similarly to the ideal sampler case available in the literature.
However, since the regulation of Raf isoforms is complex and cell-specific [12], [18], [22], [35], we initially estimated the feedback/cross-talk structure of the cascade using topological modeling.
We began by using the main structure of the MAPK cascade (steps 1 11) originally given by Heinrich et al. [24], and then included feedback (steps 13, 15, 16, 18), cross-talk (steps 12, 14, 17, 19), and dual phosphorylation of ERK (steps 8 11) components [28] [30].
The structure of the phosphorylation cascade starting from two redundant osmosensors (Sho1p and Sln1p) and leading to the transcriptional regulation of glycerol production for osmotic balance is generally agreed upon.
However, the NF model also exhibits a threshold of ERK activation at low RasGTP levels as a result of the multi-tier, multi-site phosphorylation structure of the MAPK/ERK cascade [ 2].
Thanks to the detailed molecular knowledge of sex determination in D. melanogaster and the simple structure of the genetic cascade, we are able to formulate clear hypotheses for the consequences of recruitment of Sxl on the molecular evolution of Sxl itself and its downstream targets.
Agreement between our immunofluorescence data and model predictions over the spinous and granular layers suggests that the network structure of the canonical signaling cascade with the specified feedback loops is sufficient to reproduce key features of the extended spatial phosphorylation gradient of ERK-MAPK components observed in human skin.
