GTRAP3-18 interacts with and reduces the activity of the neuronal specific Na ؉ /K ؉ glutamate transporter, EAAC1 both in vitro and in vivo. GTRAP3-18 and the related isoform, JM4, are distant relatives of the Rab GTPase-interacting factor PRA1, and share a topology of four transmembrane domains and cytosolic termini. GTRAP3-18 and JM4 are resident endoplasmic reticulum (ER) proteins. The physiological role of GTRAP3-18 is poorly understood. We demonstrate for the first time that GTRAP3-18 is a regulator of ER protein trafficking. Expression of GTRAP3-18 delays the ER exit of EAAC1, as well as other members of the excitatory amino acid transporter family. GTRAP3-18 uses hydrophobic domain interactions in the ER membrane to self-associate and cytoplasmic interactions at the C terminus to regulate trafficking. The features of GTRAP3-18 activity are consistent with recent phylogenic sequence analyses suggesting GTRAP3-18 and JM4 be reclassified as mammalian isoforms of the yeast protein family Yip, Yip6b, and Yip6a, respectively.We identified GTRAP3-18 3 (glutamate transporter-associated protein of EAAT3), a 22-kDa protein that is dynamically induced by retinoic acid both in vitro and in vivo and inhibits the activity of EAAC1 in a dose-dependent manner (GeneID 66028) (1). EAAC1 (human nomenclature EAAT3) is an isoform of the plasma membrane glutamate transporter family localized to glutamatergic and GABAergic neuronal populations and is an important physiological component of normal and abnormal synaptic transmission (2-5). Antisense reduction in GTRAP3-18 or removal of the C-terminal interaction site eliminates GTRAP3-18-mediated alterations of EAAC1 activity (1). The mechanism of this activity was unknown but speculated to be related to interaction-dependent alterations to EAAC1 protein conformation or transport activity before cell surface delivery.
The described method allows the precise analysis and elimination of motion artifacts in CLSM volume scans, in conjunction with the capability to reconstruct SNP structures even in the presence of severe ACM. The robustness and automation of the described algorithms require ongoing development, but this will provide a sound basis for extended studies of corneal nerve regeneration or degeneration and for use in clinical practice.
The key advances embodied in the proposed technique are its high degree of integration and automation (both for image acquisition and image processing) and the resulting short duration of CCM. By providing an easy-to-use tool for obtaining large-scale mosaic images of the SNP, this technique has the potential to facilitate larger clinical trials where SNP morphology is used as a surrogate marker for peripheral neuropathy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.