The different roles of selective autophagic protein degradation in mammalian cells.

Autophagy is an intracellular pathway for bulk protein degradation and the removal of damaged organelles by lysosomes. Autophagy was previously thought to be unselective; however, studies have increasingly confirmed that autophagy-mediated protein degradation is highly regulated. Abnormal autophagic protein degradation has been associated with multiple human diseases such as cancer, neurological disability and cardiovascular disease; therefore, further elucidation of protein degradation by autophagy may be beneficial for protein-based clinical therapies. Macroautophagy and chaperone-mediated autophagy (CMA) can both participate in selective protein degradation in mammalian cells, but the process is quite different in each case. Here, we summarize the various types of macroautophagy and CMA involved in determining protein degradation. For this summary, we divide the autophagic protein degradation pathways into four categories: the post-translational modification dependent and independent CMA pathways and the ubiquitin dependent and independent macroautophagy pathways, and describe how some non-canonical pathways and modifications such as phosphorylation, acetylation and arginylation can influence protein degradation by the autophagy lysosome system (ALS). Finally, we comment on why autophagy can serve as either diagnostics or therapeutic targets in different human diseases.

Association of dopaminergic/GABAergic genes with attention deficit hyperactivity disorder in children.

Attention deficit hyperactivity disorder (ADHD) is the most commonly diagnosed neurobehavioral disorder in children and adolescents; however, its etiology is unknown. In this study, we investigated the association of five polymorphisms in dopaminergic/GABAergic genes with ADHD using polymerase chain reaction-restriction fragment length polymorphism in a group of 54 children with ADHD and 67 healthy controls. The distribution of AA genotype and A allele frequencies of rs5320 in the dopamine beta-hydroxylase gene in ADHD children differed significantly from that in healthy controls; however, no associations were found between four other polymorphisms in dopaminergic/GABAergic genes and ADHD. We also identified the best model consisting of four loci. We conclude that the rs5320 polymorphism may be considered as a genetic risk factor of ADHD, but the other four polymorphisms were not confirmed to be related directly to ADHD. The multilocus of dopaminergic/GABAergic genes acted in combination to affect susceptibility to ADHD in the children studied.