Protocol for live neuron imaging analysis of basal surface fraction and dynamic availability of the dopamine transporter using DAT-pHluorin.

Surface availability of the dopamine (DA) transporter (DAT) critically influences DA transmission. Here, we present a protocol that describes the preparation of mouse ventral midbrain neurons, the expression of a new optical sensor, DAT-pHluorin, and the utilization of this sensor to analyze the surface availability of DAT in live neurons via fluorescent microscopy. This approach allows quantitative measures of basal surface DAT fraction under genetic backgrounds of interest and live trafficking of DAT in response to psychoactive substances.

Parkinson's disease gene, Synaptojanin1, dysregulates the surface maintenance of the dopamine transporter.

Missense mutations of PARK20/SYNJ1 (synaptojanin1/Synj1) were found in complex forms of familial Parkinsonism. However, the Synj1-regulated molecular and cellular changes associated with dopaminergic dysfunction remain unknown. We now report a fast depletion of evoked dopamine and impaired maintenance of the axonal dopamine transporter (DAT) in the Synj1 haploinsufficient (Synj1+/-) neurons.

Haploinsufficiency of the Parkinson's disease gene synaptojanin1 is associated with abnormal responses to psychomotor stimulants and mesolimbic dopamine signaling.

The () gene is known to be important for dopamine-related disorders. Recent evidence has demonstrated that Synj1 deficient mice ( ) have impairments in dopaminergic synaptic vesicular recycling. However, less is known about how deficits affect the mesolimbic system, reward processing, and motivated behavior.

Parkinson's disease gene, Synaptojanin1, dysregulates the surface maintenance of the dopamine transporter.

Missense mutations of PARK20/ (synaptojanin1/Synj1) have been linked to complex forms of familial parkinsonism, however, the molecular and cellular changes associated with dopaminergic dysfunction remains unknown. We now report fast depletion of evoked dopamine (DA) and altered maintenance of the axonal dopamine transporter (DAT) in the neurons. While Synj1 has been traditionally known to facilitate the endocytosis of synaptic vesicles, we demonstrated that axons of cultured neurons exhibit an increase of total DAT but a reduction of the surface DAT, which could be exacerbated by neuronal activity.

Cocaine-regulated trafficking of dopamine transporters in cultured neurons revealed by a pH sensitive reporter.

Cocaine acts by inhibiting plasma membrane dopamine transporter (DAT) function and altering its surface expression. The precise manner and mechanism by which cocaine regulates DAT trafficking, especially at neuronal processes, are poorly understood. In this study, we engineered and validated the use of DAT-pHluorin for studying DAT localization and its dynamic trafficking at neuronal processes of cultured mouse midbrain neurons.

Synj1 haploinsufficiency causes dopamine neuron vulnerability and alpha-synuclein accumulation in mice.

Synaptojanin1 (synj1) is a phosphoinositide phosphatase with dual SAC1 and 5'-phosphatase enzymatic activities in regulating phospholipid signaling. The brain-enriched isoform has been shown to participate in synaptic vesicle (SV) recycling. More recently, recessive human mutations were identified in the two phosphatase domains of SYNJ1, including R258Q, R459P and R839C, which are linked to rare forms of early-onset Parkinsonism.