SNAP-505

Operating Instructions (The following is a recommended experimental protocol for guidance only; adjustments are required based on your specific needs)

1. Stock Solution Preparation
1.1 Solvent: Most dyes are typically dissolved in organic solvents, such as anhydrous DMSO.
1.2 Concentration Recommendation: A high-concentration stock solution of 1-10 mM.

2. Working Solution Preparation
2.1 Solvent: Cell culture medium.
2.2 Concentration Recommendation: 1 μM.
2.3 Notes: Adjust the working solution concentration as needed; prepare fresh before use.

3. Staining Procedure
3.1 Sample Type Description
3.1.1 For adherent insulin-secreting cell lines^[1][2]: Seed INS1 832/3 cells stably expressing proCpepSNAP onto HTB9-coated coverslips.
3.1.2 For primary islet cells^[1][2]: Disperse isolated islets expressing proCpepSNAP into a single-cell layer using Accutase, then seed onto HTB9-coated coverslips or 6 cm glass-bottom culture dishes; applicable to mouse primary islet β cells and human primary islet β cells.
3.1.3 For transfected adherent HeLa cells^[3]: HeLa cells expressing TERT-SNAP; trypsinization is not required for staining.
3.2 Incubation Conditions
3.2.1 For insulin-secreting cell lines and primary islet cells: Pulse-label with 1 μM SNAP-505 in culture medium for 20 min; perform a chase incubation for 10 min or 2 h according to experimental endpoint requirements.
3.2.2 For transfected adherent HeLa cells: Incubate with SNAP-505 for 15-30 min.
3.3 Washing Steps
3.3.1 For insulin-secreting cell lines and primary islet cells: After pulse labeling, wash 3 times with medium containing 5 mM glucose, 5 min each time.
3.3.2 For transfected adherent HeLa cells: Wash after staining (follow the protocol recommended by NEB; usually wash 1-2 times with PBS or medium, 5 min each time).

4. Control Setup
4.1 Set up negative controls: Stain untransfected HeLa cells under the same experimental conditions.

5. Detection and Analysis
5.1 Instrument Types: Confocal microscope, total internal reflection fluorescence (TIRF) microscope, laser scanning fluorescence microscope.
5.2 Excitation/Emission Wavelengths: Excitation with a 488 nm laser (intrinsic Ex/Em ≈ 504/532 nm); emission detection range is set according to the instrument (e.g., 494-690 nm spectral window for Zeiss LSM780); SNAP-505 produces green fluorescence (cyan pseudocolor can be used for visualization).
5.3 Result Analysis
5.3.1 Fluorescence Localization:
5.3.1.1 For cells expressing proCpepSNAP: Labeled proCpepSNAP localizes to nascent insulin granules, the Golgi apparatus, and the endoplasmic reticulum (ER) depending on the chase incubation time.
5.3.1.2 For HeLa cells expressing TERT-SNAP: SNAP-505 localizes mainly to the nucleus both before and after incubation with 500 μM H₂O₂ for 3 hours.
5.3.2 Quantitative Analysis:
5.3.2.1 Count the number of nascent granules (150-300 nm in diameter) and normalize to the total number of proCpepSNAP-labeled cells.
5.3.2.2 Detect fluorescence intensity and normalize to the total number of proCpepSNAP-labeled cells; measure the total SNAP-505 fluorescence intensity per cell to confirm consistent target protein expression levels among groups.
5.3.2.3 Calculate the distance between granules and the Golgi apparatus using the distance transform method.
5.3.2.4 Determine the colocalization of SNAP-505 fluorescence with Golgi/ER markers using the Mander's correlation coefficient; quantify the proportion of proCpepSNAP fluorescence colocalized with Golgi markers (GM130, TGN38) and with ER markers (BiP) to evaluate ER-to-Golgi protein trafficking.
5.3.2.5 Count the number of nascent insulin granules labeled as punctate structures by SNAP-505 per cell after a 2-hour chase incubation.

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.