Knockouts of various alternative pathway components have demonstrated roles in maturation of B cells [23] and induction of TH17 cells [24], as well as differentiation of osteoclasts [8], suggesting that this pathway might be a relatively specific target for autoimmune diseases, especially those associated with bone loss.
PKR, however, is involved in various, alternative signaling pathways and has diverse roles (Jagus et al, 1999).
Away from this unrealistic case, when the whole set of kinetic constants of the promoter-state graph contains directed cycles with heterogeneous transitions, alternative pathways (of various length and duration) and includes backward, incoming and outgoing transitions then the system can still demonstrate a periodic activity (ie. non-real eigenvalues).
Various reasons, including up-regulation of alternative pathways, autoantibodies, and impairment of the retinal pigment epithelium (RPE) have been implicated [ 8].
Besides the ROS-mediated redox activity, it may catalyze reactions that can be considered as metabolic escape routes providing alternative pathways for NAD(P H under various environmental stress conditions.
In this way, a set of important temporal, spatial, orientational, and contextual aspects is added, which is crucial for modulation and regulation of alternative pathways by promoting interactions between various signaling proteins.
This is because bio-systems have complex structures consisting of branches, alternative pathways and loops, as well as various kinetic parameters differing in orders of magnitudes [ 6, 24].
In addition, Dicer-independent, and probably Drosha-independent maturing of miRNAs is possible, suggesting alternative pathways and different roles for Dicer and Drosha in various cancers [ 49, 50].
Here we review the various alternative approaches to target the various protein classes termed as cancer TARGETases in DSB repair pathway to obtain more beneficial and selective therapy.
However, alternative pathways, such as methionine synthesis from homocysteine by B12-independent MetE, have evolved in various organisms [ 69, 70].
