High impact information on Syngr2

• Our previous studies in PC12 cells demonstrated that synaptogyrin or its nonneuronal paralog cellugyrin targets efficiently to synaptic-like microvesicles (SLMVs) and dramatically increases the synaptophysin content of SLMVs (Belfort, G. M., and Kandror, K. V. (2003) J. Biol. Chem. 278, 47971-47978) [1].
• Here, we explored the mechanism of these phenomena and found that ectopic expression of cellugyrin increases the number of SLMVs in PC12 cells [1].
• Mutagenesis studies revealed that cellugyrin's hydrophilic cytoplasmic domains are not involved in vesicle biogenesis, whereas small conserved hydrophobic hairpins in the first luminal loop and the carboxyl terminus of cellugyrin were found to be critical for the formation of SLMVs [1].
• In rat adipose cells, intracellular Glut4 resides in two distinct vesicular populations one of which contains cellugyrin whereas another lacks this protein (Kupriyanova, T. A., and Kandror, K. V. (2000) J. Biol. Chem. 275, 36263--36268) [2].
• Cellugyrin-negative vesicles are translocated to the cell surface after insulin stimulation, whereas cellugyrin-positive vesicles maintain intracellular localization both in the absence and in the presence of insulin and, therefore, may be involved in interendosomal protein transport [2].

Biological context of Syngr2

• Cellugyrin induces biogenesis of synaptic-like microvesicles in PC12 cells [1].

Anatomical context of Syngr2

• We suggest that cellugyrin represents a specific marker of a functionally distinct population of Glut4 vesicles that permanently maintains its intracellular localization and is not recruited to the plasma membrane by insulin [3].
• We have prepared a monoclonal antibody against a novel component protein of Glut4 vesicles and have identified this protein as cellugyrin, a ubiquitously expressed homologue of a major synaptic vesicle protein, synaptogyrin [3].
• In chimeric studies, these regions were sufficient to relocalize cellugyrin, a nonneuronal form of synaptogyrin, from nonsynaptic regions such as the sensory dendrites and the cell body to synaptic vesicles [4].

Associations of Syngr2 with chemical compounds

• By means of sucrose gradient centrifugation, immunoadsorption, and confocal microscopy, we have shown that virtually all cellugyrin is co-localized with Glut4 in the same vesicles [3].

Other interactions of Syngr2

• Cellugyrin is a marker for a distinct population of intracellular Glut4-containing vesicles [3].

References