Enzymatic O-glycosylation of kappa-caseinomacropeptide by ovine mammary Golgi membranes

The organization and function of the Golgi apparatus in dendrite development and neurological disorders

Dendrites are specialized neuronal compartments that sense, integrate and transfer information in the neural network. Their development is tightly controlled and abnormal dendrite morphogenesis is strongly linked to neurological disorders. While dendritic morphology ranges from relatively simple to extremely complex for a specified neuron, either requires a functional secretory pathway to continually replenish proteins and lipids to meet dendritic growth demands. The Golgi apparatus occupies the center of the secretory pathway and is regulating posttranslational modifications, sorting, transport, and signal transduction, as well as acting as a non-centrosomal microtubule organization center. The neuronal Golgi apparatus shares common features with Golgi in other eukaryotic cell types but also forms distinct structures known as Golgi outposts that specifically localize in dendrites. However, the organization and function of Golgi in dendrite development and its impact on neurological disorders is just emerging and so far lacks a systematic summary. We describe the organization of the Golgi apparatus in neurons, review the current understanding of Golgi function in dendritic morphogenesis, and discuss the current challenges and future directions.

Activation of D1 receptors affects human reactivity and flexibility to valued cues

Reward-predicting cues motivate goal-directed behavior, but in unstable environments humans must also be able to flexibly update cue-reward associations. While the capacity of reward cues to trigger motivation ('reactivity') as well as flexibility in cue-reward associations have been linked to the neurotransmitter dopamine in humans, the specific contribution of the dopamine D1 receptor family to these behaviors remained elusive. To fill this gap, we conducted a randomized, placebo-controlled, double-blind pharmacological study testing the impact of three different doses of a novel D1 agonist (relative to placebo) on reactivity to reward-predicting cues (Pavlovian-to-instrumental transfer) and flexibility of cue-outcome associations (reversal learning). We observed that the impact of the D1 agonist crucially depended on baseline working memory functioning, which has been identified as a proxy for baseline dopamine synthesis capacity. Specifically, increasing D1 receptor stimulation strengthened Pavlovian-to-instrumental transfer in individuals with high baseline working memory capacity. In contrast, higher doses of the D1 agonist improved reversal learning only in individuals with low baseline working memory functioning. Our findings suggest a crucial and baseline-dependent role of D1 receptor activation in controlling both cue reactivity and the flexibility of cue-reward associations.