One distal branch of the pathway, containing Stt7/Stn7, affects post-translational modification of existing proteins by phosphorylation. The second branch, consisting of CSK, controls photosystem stoichiometry by means of regulation of transcription of chloroplast genes for reaction centre apoproteins. Upstream of the point of divergence of the two branches is plastoquinone itself. It remains to be seen whether two separate plastoquinone/quinolbinding sensors initiate the two signal transduction events, or whether a single plastoquinone-binding redox sensor, as yet unidentified, controls both CSK and the LHC II kinase. The first possibility, that plastoquinone redox state is sensed by two independent redox sensors – CSK and LHC II kinase is supported by the available evidence and consistent with a Reversine recent model for redox control of Stn7. It will also be important to resolve the evolutionary origin of these related redox signal transduction pathways. Plastoquinone itself is common to electron transport in both chloroplasts and cyanobacteria, and in both cases, both state transitions and photosystem stoichiometry appear to be initiated by changes plastoquinone redox state. CSK and its homologues are likely to be involved in transcriptional control in all cases, while the differing peripheral light-harvesting antenna systems of cyanobacteria and chloroplasts make the participation of an LHC II kinase and phosphatase in cyanobacterial state transition unlikely. Nevertheless, quinone-level redox control seems to be a conserved feature of regulation in a very wide range of bioenergetic systems and it is usual in prokaryotic signal transduction for a single environmental input to exert effects at multiple levels of gene expression, from transcription to posttranslational modification of pre-existing proteins. Patients suffering from diabetes are at a greater risk of thrombotic complications and exhibit a much higher incidence of cardiovascular disease as well as an increased rate of mortality due to ischemic heart disease. Platelets from diabetic patients have been shown to exhibit increased adhesion, secretion and aggregation, processes that promote thrombotic complication in diabetics. Increased platelet reactivity in diabetic patients plays a critical role in initiation and progression of thrombosis leading to cardiovascular disease, diabetic nephropathy, retinopathy as well as peripheral artery disease. Reports that abnormal platelet function occurs not only in platelet-rich plasma but also in washed platelets imply that the mechanism of increased platelet reactivity reside within the platelets. It has been shown that insulin inhibits platelet activation. Moreover, the ability of insulin to inhibit platelet function has been shown to be lacking or diminished in insulin-resistant patients. The direct anti-platelet action of insulin is possibly mediated via regulation of adenylyl cyclase. ADP or thrombin, agonists that induce platelet aggregation, lower basal cyclic AMP levels via stimulation of Gia2, a G protein that inhibits adenylyl cyclase.