Laforin binds PTG at PTG’s binding site with GS (21). Laforin would therefore downregulate GS by physically AZD8055 datasheet outcompeting PTG-PP1 off of GS. GSK3 is the main inhibitor of GS, through phosphorylation of five phosphoregulatory sites on GS (37). Laforin activates GSK3 through dephosphorylation of GSK3 (25, 26). Laforin-activated GSK3 would inactivate GS. In sum, absence Inhibitors,research,lifescience,medical of laforin would lead to excess GS activity, GS/BE imbalance, formation of insoluble polyglucosans, and their accumulation into LBs. The concept of malin and laforin agonistically acting to decrease GS activity in order to promote the right GS/BE balance is in contrast with the observation that malin polyubiquitinates

laforin, targeting it for destruction (29). A possible explanation Inhibitors,research,lifescience,medical follows: LBs are much more phosphorylated than glycogen, and are in fact more similar to amylopectin than to glycogen. Laforin is able to dephosphorylate amylopectin (38). Therefore, it is possible that laforin could also dephosphorylate LBs, and

that the high phosphate content in LBs, compared to normal glycogen, may be a direct consequence of the mutated laforin. Interestingly, glycogen binding appears to inhibit laforin activity (39). Laforin inhibition may be a feedback mechanism Inhibitors,research,lifescience,medical to preserve a certain degree of phosphorylation of the glycogen molecule. The role of glycogen dephosphorylation is not clear, but it may be correlated to the maintenance of a properly branched polysaccharide. If laforin activity needs to be kept in check (by glycogen inhibition) to avoid over dephosphorylation of glycogen, it is possible that a mutated malin would lead to lack of ubiquitination and destruction of laforin. Inhibitors,research,lifescience,medical Could excess laforin cause such an imbalance of glycogen dephosphorylation to lead to the formation of LBs? Finally, polyglucosans are even more potent inhibitors of laforin DSP activity than normal glycogen. In that case, the initial formation

of polyglucosans (either Inhibitors,research,lifescience,medical because of mutated laforin, malin or another yet unknown protein) would be aggravated by the further inhibition of any residual laforin activity. Much information has been gained in LD, but knowledge remains very tentative. Clearly more data are either needed to understand the mechanisms causing LD, and maybe then to find a way to make this disease go away.
Influential French press media recently paid particular attention to the provoked termination of life, particularly regarding some cases of “muscular dystrophy” in two different European countries (1–4). It referred to the reactions concerning three cases of euthanasia of persons living with the aid of respiratory assistance, aged 61, 69 and 51 years. It expressed the major opinion lines of the supporters in favour of a “End-of-life Decisions” legislation, in flat contradiction to the dogma “Life is Sacred”, as a matter of fact, a recurrent debate (5).