An important part of cellular signalling is the role of protein translocation. In an unstimulated state, proteins are kept in a different cellular compartment to where they exert their effect when activated. An example of this is NF-kappa B. In its inactive state, NF-kappa B is sequestered in the cytoplasm by I kappa Bs. Upon activation, I kappa B proteins are phosphorylated and then degraded via the ubiquitin pathway. This allows the NF-kappa B protein to enter the nucleus and exert effects on the expression of specific genes that have DNA-binding sites for NF-kappa B. The activation of these genes leads to the given physiological response, for example, an inflammatory or immune response, a cell survival response, or cellular proliferation.
When using CCD-based screening systems, these assays require an additional stain to identify the cell nucleus, and separate image captures for each colour used. These images must then be analysed off-line, which takes additional time, using different algorithms to assess cytoplasm to nuclear ratio, or cytoplasm to membrane ratio.
acumen has been widely used to study translocation events. It provides a fast, simple method to study protein translocation, without the requirement for off-line complex image analysis algorithms. acumen hci can be used to determine the movement of proteins between the cytoplasm to plasma membrane, or between the nucleus and cytoplasm.