Munc18-1 Antibody [G23A10] | Primary Antibodies

Application: Reactivity: Human, Mouse, Rat

Lane 1: Mouse brain, Lane 2: Rat brain

Usage Information

Dilution
WB1:1000 IHC1:2000 IF1:100 FCM1:500

Application
WB, IHC, IF, FCM

Reactivity
Human, Mouse, Rat

Source
Rabbit Monoclonal Antibody

Storage Buffer
PBS, pH 7.2+50% Glycerol+0.05% BSA+0.01% NaN3

Storage (from the date of receipt)
-20°C (avoid freeze-thaw cycles), 2 years

Predicted MW Observed MW
67 kDa 67 kDa,36 kDa
^*Why do the predicted and actual molecular weights differ? The following reasons may explain differences between the predicted and actual protein molecular weight. Post-translational modifications(e.g., phosphorylation, glycosylation); Splice variants and isoforms; Relative charge; Multimerization.

Positive Control	Human brain tissue; Human cerebellum tissue; Mouse hippocampus tissue; Rat hippocampus tissue; Mouse brain tissue; Rat cerebellum tissue; Mouse cerebrum tissue; Rat brain tissue; U-87 MG cells
Negative Control	Mouse liver tissue; Rat kidney tissue; Mouse kidney tissue; Rat liver tissue; Mouse hippocampus tissue; Rat hippocampus tissue; Mouse skeletal muscle tissue; Rat liver tissue; Rat skeletal muscle tissue; Human skeletal muscle tissue; Rat primary neural/glia cells; Mouse primary neural/glia cells; Mouse primary neuron cells

Experimental Methods

WB
Experimental Protocol: Sample preparation 1. Tissue: Lyse the tissue sample by adding an appropriate volume of ice-cold RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail)，and homogenize the tissue at a low temperature or lyse it by sonication on ice, then incubate on ice for 30 minutes. 2. Adherent cell: Aspirate the culture medium and wash the cells with ice-cold PBS twice. Lyse the cells by adding an appropriate volume of RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail) , sonicate to lyse the cells, and incubate on ice for 30 minutes. 3. Suspension cell: Transfer the culture medium to a pre-cooled centrifuge tube. Centrifuge and aspirate the supernatant. Wash the cells with ice-cold PBS twice. Lyse the cells by adding an appropriate volume of RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail) , sonicate to lyse the cells, and incubate on ice for 30 minutes. 4. Place the lysate into a pre-cooled microcentrifuge tube. Centrifuge at 4°C for 15 min. Collect the supernatant; 5. Remove a small volume of lysate to determine the protein concentration; 6. Combine the lysate with protein loading buffer. Boil 20 µL sample under 95-100°C for 5 min. Centrifuge for 5 min after cool down on ice. Electrophoretic separation 1. According to the concentration of extracted protein, load appropriate amount of protein sample and marker onto SDS-PAGE gels for electrophoresis. Recommended separating gel (lower gel) concentration: 10%. Reference Table for Selecting SDS-PAGE Separation Gel Concentrations 2. Power up 80V for 30 minutes. Then the power supply is adjusted (110 V~150 V), the Marker is observed, and the electrophoresis can be stopped when the indicator band of the predyed protein Marker where the protein is located is properly separated. (Note that the current should not be too large when electrophoresis, too large current (more than 150 mA) will cause the temperature to rise, affecting the result of running glue. If high currents cannot be avoided, an ice bath can be used to cool the bath.) Transfer membrane 1. Take out the converter, soak the clip and consumables in the pre-cooled converter; 2. Activate PVDF membrane with methanol for 1 min and rinse with transfer buffer; 3. Install it in the order of "black edge of clip - sponge - filter paper - filter paper - glue -PVDF membrane - filter paper - filter paper - sponge - white edge of clip"; 4. The protein was electrotransferred to PVDF membrane. ( 0.45 µm PVDF membrane is recommended ) Reference Table for Selecting PVDF Membrane Pore Size Specifications Recommended conditions for wet transfer: 200 mA, 120 min. ( Note that the transfer conditions can be adjusted according to the protein size. For high-molecular-weight proteins, a higher current and longer transfer time are recommended. However, ensure that the transfer tank remains at a low temperature to prevent gel melting.) Block 1. After electrotransfer, wash the film with TBST at room temperature for 5 minutes; 2. Incubate the film in the blocking solution for 1 hour at room temperature; 3. Wash the film with TBST for 3 times, 5 minutes each time. Antibody incubation 1. Use 5% skim milk powder to prepare the primary antibody working liquid (recommended dilution ratio for primary antibody 1:1000), gently shake and incubate with the film at 4°C overnight; 2. Wash the film with TBST 3 times, 5 minutes each time; 3. Add the secondary antibody to the blocking solution and incubate with the film gently at room temperature for 1 hour; 4. After incubation, wash the film with TBST 3 times for 5 minutes each time. Antibody staining 1. Add the prepared ECL luminescent substrate (or select other color developing substrate according to the second antibody) and mix evenly; 2. Incubate with the film for 1 minute, remove excess substrate (keep the film moist), wrap with plastic film, and expose in the imaging system.

WB

Experimental Protocol:

Sample preparation

1. Tissue: Lyse the tissue sample by adding an appropriate volume of ice-cold RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail)，and homogenize the tissue at a low temperature or lyse it by sonication on ice, then incubate on ice for 30 minutes.

2. Adherent cell: Aspirate the culture medium and wash the cells with ice-cold PBS twice. Lyse the cells by adding an appropriate volume of RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail) , sonicate to lyse the cells, and incubate on ice for 30 minutes.

3. Suspension cell: Transfer the culture medium to a pre-cooled centrifuge tube. Centrifuge and aspirate the supernatant. Wash the cells with ice-cold PBS twice. Lyse the cells by adding an appropriate volume of RIPA/NP-40 Lysis Buffer (containing Protease Inhibitor Cocktail) , sonicate to lyse the cells, and incubate on ice for 30 minutes.

4. Place the lysate into a pre-cooled microcentrifuge tube. Centrifuge at 4°C for 15 min. Collect the supernatant;

5. Remove a small volume of lysate to determine the protein concentration;

6. Combine the lysate with protein loading buffer. Boil 20 µL sample under 95-100°C for 5 min. Centrifuge for 5 min after cool down on ice.

Electrophoretic separation

1. According to the concentration of extracted protein, load appropriate amount of protein sample and marker onto SDS-PAGE gels for electrophoresis. Recommended separating gel (lower gel) concentration: 10%. Reference Table for Selecting SDS-PAGE Separation Gel Concentrations

2. Power up 80V for 30 minutes. Then the power supply is adjusted (110 V~150 V), the Marker is observed, and the electrophoresis can be stopped when the indicator band of the predyed protein Marker where the protein is located is properly separated. (Note that the current should not be too large when electrophoresis, too large current (more than 150 mA) will cause the temperature to rise, affecting the result of running glue. If high currents cannot be avoided, an ice bath can be used to cool the bath.)

Transfer membrane

1. Take out the converter, soak the clip and consumables in the pre-cooled converter;

2. Activate PVDF membrane with methanol for 1 min and rinse with transfer buffer;

3. Install it in the order of "black edge of clip - sponge - filter paper - filter paper - glue -PVDF membrane - filter paper - filter paper - sponge - white edge of clip";

4. The protein was electrotransferred to PVDF membrane. ( 0.45 µm PVDF membrane is recommended ) Reference Table for Selecting PVDF Membrane Pore Size Specifications

Recommended conditions for wet transfer: 200 mA, 120 min.

( Note that the transfer conditions can be adjusted according to the protein size. For high-molecular-weight proteins, a higher current and longer transfer time are recommended. However, ensure that the transfer tank remains at a low temperature to prevent gel melting.)

Block

1. After electrotransfer, wash the film with TBST at room temperature for 5 minutes;

2. Incubate the film in the blocking solution for 1 hour at room temperature;

3. Wash the film with TBST for 3 times, 5 minutes each time.

Antibody incubation

1. Use 5% skim milk powder to prepare the primary antibody working liquid (recommended dilution ratio for primary antibody 1:1000), gently shake and incubate with the film at 4°C overnight;

2. Wash the film with TBST 3 times, 5 minutes each time;

3. Add the secondary antibody to the blocking solution and incubate with the film gently at room temperature for 1 hour;

4. After incubation, wash the film with TBST 3 times for 5 minutes each time.

Antibody staining

1. Add the prepared ECL luminescent substrate (or select other color developing substrate according to the second antibody) and mix evenly;

2. Incubate with the film for 1 minute, remove excess substrate (keep the film moist), wrap with plastic film, and expose in the imaging system.

IF
Experimental Protocol: Sample Preparation 1. Adherent Cells: Place a clean, sterile coverslip in a culture dish. Once the cells grow to near confluence as a monolayer, remove the coverslip for further use. 2. Suspension Cells: Seed the cells onto a clean, sterile slide coated with poly-L-lysine. 3. Frozen Sections: Allow the slide to thaw at room temperature. Wash it with pure water or PBS for 2 times, 3 minutes each time. 4. Paraffin Sections: Deparaffinization and rehydration. Wash the slide with pure water or PBS for 3 times, 3 minutes each time. Then perform antigen retrieval. Fixation 1. Fix the cell coverslips/spots or tissue sections at room temperature using a fixative such as 4% paraformaldehyde (4% PFA) for 10-15 minutes. 2. Wash the sample with PBS for 3 times, 3 minutes each time. Permeabilization 1.Add a detergent such as 0.1–0.3% Triton X-100 to the sample and incubate at room temperature for 10–20 minutes. (Note: This step is only required for intracellular antigens. For antigens expressed on the cell membrane, this step is unnecessary.) Wash the sample with PBS for 3 times, 3 minutes each time. Blocking Add blocking solution and incubate at room temperature for at least 1 hour. (Common blocking solutions include: serum from the same source as the secondary antibody, BSA, or goat serum.) Note: Ensure the sample remains moist during and after the blocking step to prevent drying, which can lead to high background. Immunofluorescence Staining (Day 1) 1. Remove the blocking solution and add the diluted primary antibody. 2. Incubate the sample in a humidified chamber at 4°C overnight. Immunofluorescence Staining (Day 2) 1. Remove the primary antibody and wash with PBST for 3 times, 5 minutes each time. 2. Add the diluted fluorescent secondary antibody and incubate in the dark at 4°C for 1–2 hours. 3. Remove the secondary antibody and wash with PBST for 3 times, 5 minutes each time. 4. Add diluted DAPI and incubate at room temperature in the dark for 5–10 minutes. 5. Wash with PBST for 3 times, 5 minutes each time. Mounting 1. Mount the sample with an anti-fade mounting medium. 2. Allow the slide to dry at room temperature overnight in the dark. 3. Store the slide in a slide storage box at 4°C, protected from light.

IF

Experimental Protocol:

Sample Preparation

1. Adherent Cells: Place a clean, sterile coverslip in a culture dish. Once the cells grow to near confluence as a monolayer, remove the coverslip for further use.

2. Suspension Cells: Seed the cells onto a clean, sterile slide coated with poly-L-lysine.

3. Frozen Sections: Allow the slide to thaw at room temperature. Wash it with pure water or PBS for 2 times, 3 minutes each time.

4. Paraffin Sections: Deparaffinization and rehydration. Wash the slide with pure water or PBS for 3 times, 3 minutes each time. Then perform antigen retrieval.

Fixation

1. Fix the cell coverslips/spots or tissue sections at room temperature using a fixative such as 4% paraformaldehyde (4% PFA) for 10-15 minutes.

2. Wash the sample with PBS for 3 times, 3 minutes each time.

Permeabilization

1.Add a detergent such as 0.1–0.3% Triton X-100 to the sample and incubate at room temperature for 10–20 minutes.

(Note: This step is only required for intracellular antigens. For antigens expressed on the cell membrane, this step is unnecessary.)

Wash the sample with PBS for 3 times, 3 minutes each time.

Blocking

Add blocking solution and incubate at room temperature for at least 1 hour. (Common blocking solutions include: serum from the same source as the secondary antibody, BSA, or goat serum.)

Note: Ensure the sample remains moist during and after the blocking step to prevent drying, which can lead to high background.

Immunofluorescence Staining (Day 1)

1. Remove the blocking solution and add the diluted primary antibody.

2. Incubate the sample in a humidified chamber at 4°C overnight.

Immunofluorescence Staining (Day 2)

1. Remove the primary antibody and wash with PBST for 3 times, 5 minutes each time.

2. Add the diluted fluorescent secondary antibody and incubate in the dark at 4°C for 1–2 hours.

3. Remove the secondary antibody and wash with PBST for 3 times, 5 minutes each time.

4. Add diluted DAPI and incubate at room temperature in the dark for 5–10 minutes.

5. Wash with PBST for 3 times, 5 minutes each time.

Mounting

1. Mount the sample with an anti-fade mounting medium.

2. Allow the slide to dry at room temperature overnight in the dark.

3. Store the slide in a slide storage box at 4°C, protected from light.

IHC
Experimental Protocol： Deparaffinization/Rehydration 1. Deparaffinize/hydrate sections: 2. Incubate sections in three washes of xylene for 5 min each. 3. Incubate sections in two washes of 100% ethanol for 10 min each. 4. Incubate sections in two washes of 95% ethanol for 10 min each. 5. Wash sections two times in dH2O for 5 min each. 6.Antigen retrieval: For Citrate: Heat slides in a microwave submersed in 1X citrate unmasking solution until boiling is initiated; continue with 10 min at a sub-boiling temperature (95°-98°C). Cool slides on bench top for 30 min. Staining 1. Wash sections in dH2O three times for 5 min each. 2. Incubate sections in 3% hydrogen peroxide for 10 min. 3. Wash sections in dH2O two times for 5 min each. 4. Wash sections in wash buffer for 5 min. 5. Block each section with 100–400 µl of blocking solution for 1 hr at room temperature. 6. Remove blocking solution and add 100–400 µl primary antibody diluent in to each section. Incubate overnight at 4°C. 7. Remove antibody solution and wash sections with wash buffer three times for 5 min each. 8. Cover section with 1–3 drops HRPas needed. Incubate in a humidified chamber for 30 min at room temperature. 9. Wash sections three times with wash buffer for 5 min each. 10. Add DAB Chromogen Concentrate to DAB Diluent and mix well before use. 11. Apply 100–400 µl DAB to each section and monitor closely. 1–10 min generally provides an acceptable staining intensity. 12. Immerse slides in dH2O. 13. If desired, counterstain sections with hematoxylin. 14. Wash sections in dH2O two times for 5 min each. 15. Dehydrate sections: Incubate sections in 95% ethanol two times for 10 sec each; Repeat in 100% ethanol, incubating sections two times for 10 sec each; Repeat in xylene, incubating sections two times for 10 sec each. 16. Mount sections with coverslips and mounting medium.

IHC

Experimental Protocol：

Deparaffinization/Rehydration

1. Deparaffinize/hydrate sections:

2. Incubate sections in three washes of xylene for 5 min each.

3. Incubate sections in two washes of 100% ethanol for 10 min each.

4. Incubate sections in two washes of 95% ethanol for 10 min each.

5. Wash sections two times in dH2O for 5 min each.

6.Antigen retrieval: For Citrate: Heat slides in a microwave submersed in 1X citrate unmasking solution until boiling is initiated; continue with 10 min at a sub-boiling temperature (95°-98°C). Cool slides on bench top for 30 min.

Staining

1. Wash sections in dH2O three times for 5 min each.

2. Incubate sections in 3% hydrogen peroxide for 10 min.

3. Wash sections in dH2O two times for 5 min each.

4. Wash sections in wash buffer for 5 min.

5. Block each section with 100–400 µl of blocking solution for 1 hr at room temperature.

6. Remove blocking solution and add 100–400 µl primary antibody diluent in to each section. Incubate overnight at 4°C.

7. Remove antibody solution and wash sections with wash buffer three times for 5 min each.

8. Cover section with 1–3 drops HRPas needed. Incubate in a humidified chamber for 30 min at room temperature.

9. Wash sections three times with wash buffer for 5 min each.

10. Add DAB Chromogen Concentrate to DAB Diluent and mix well before use.

11. Apply 100–400 µl DAB to each section and monitor closely. 1–10 min generally provides an acceptable staining intensity.

12. Immerse slides in dH2O.

13. If desired, counterstain sections with hematoxylin.

14. Wash sections in dH2O two times for 5 min each.

15. Dehydrate sections: Incubate sections in 95% ethanol two times for 10 sec each; Repeat in 100% ethanol, incubating sections two times for 10 sec each; Repeat in xylene, incubating sections two times for 10 sec each.

16. Mount sections with coverslips and mounting medium.

Datasheet & SDS

Biological Description

Specificity
Munc18-1 Antibody (Rabbit mAb) [G23A10] detects endogenous levels of total Munc18-1 protein.

Subcellular Location
Cytoplasm, Membrane

Uniprot ID
P61764

Clone
G23A10

Synonym(s)
Syntaxin-binding protein 1, Protein unc-18 homolog 1, Protein unc-18 homolog A, Unc18-1, Unc-18A, Stxbp1

Background
Munc18‑1, also known as syntaxin‑binding protein 1 (STXBP1), is a neuronal Sec1/Munc18 family protein that acts as a central organizer of the SNARE machinery controlling fast synaptic vesicle exocytosis at chemical synapses. The protein forms a multi‑domain arch that cradles syntaxin‑1 and presents distinct interaction surfaces for the closed conformation of syntaxin‑1, the N‑terminal syntaxin‑1 peptide, and assembled SNARE complexes, allowing it to stabilize syntaxin‑1, guide SNARE assembly, and remain associated during fusion. Munc18‑1 binds tightly to closed syntaxin‑1 and functions as a molecular chaperone that supports correct folding and axonal targeting of syntaxin‑1, which is required to maintain a competent pool of t‑SNAREs at presynaptic active zones and to prevent syntaxin mislocalization or degradation. During vesicle priming, Munc18‑1 cooperates with Munc13‑1 to open syntaxin‑1 and to template assembly of the ternary SNARE complex containing syntaxin‑1, SNAP‑25, and VAMP2/synaptobrevin‑2, so that the complex forms in a spatially and temporally controlled way that supports rapid Ca²⁺‑triggered fusion. Structural and functional analyses indicate that domain 3a of Munc18‑1, particularly helices 11 and 12, contacts the central region of the VAMP2 SNARE motif and aligns it with syntaxin‑1 and SNAP‑25, an interaction that is essential for efficient SNARE templating and for generating fusion‑competent trans‑SNARE complexes. The same scaffold stabilizes partially zippered SNARE assemblies at the plasma membrane and is proposed to help maintain vesicles in a primed state, ready for rapid membrane merger once synaptotagmin senses Ca²⁺ and releases the final constraints on fusion. Loss of Munc18‑1 function causes a near‑complete block of synaptic vesicle exocytosis and large dense‑core vesicle release, while graded reductions in Munc18‑1 reduce vesicle docking, cut the size of the readily releasable pool, and impair neurotransmitter output. Heterozygous de novo mutations in STXBP1 that alter Munc18‑1 stability or its interaction with syntaxin‑1 and SNARE complexes are linked to early infantile epileptic encephalopathy and related neurodevelopmental syndromes, where disturbed synaptic vesicle priming and reduced synchronous release correlate with epilepsy, intellectual disability, and movement abnormalities.

Background

Munc18‑1, also known as syntaxin‑binding protein 1 (STXBP1), is a neuronal Sec1/Munc18 family protein that acts as a central organizer of the SNARE machinery controlling fast synaptic vesicle exocytosis at chemical synapses. The protein forms a multi‑domain arch that cradles syntaxin‑1 and presents distinct interaction surfaces for the closed conformation of syntaxin‑1, the N‑terminal syntaxin‑1 peptide, and assembled SNARE complexes, allowing it to stabilize syntaxin‑1, guide SNARE assembly, and remain associated during fusion. Munc18‑1 binds tightly to closed syntaxin‑1 and functions as a molecular chaperone that supports correct folding and axonal targeting of syntaxin‑1, which is required to maintain a competent pool of t‑SNAREs at presynaptic active zones and to prevent syntaxin mislocalization or degradation. During vesicle priming, Munc18‑1 cooperates with Munc13‑1 to open syntaxin‑1 and to template assembly of the ternary SNARE complex containing syntaxin‑1, SNAP‑25, and VAMP2/synaptobrevin‑2, so that the complex forms in a spatially and temporally controlled way that supports rapid Ca²⁺‑triggered fusion. Structural and functional analyses indicate that domain 3a of Munc18‑1, particularly helices 11 and 12, contacts the central region of the VAMP2 SNARE motif and aligns it with syntaxin‑1 and SNAP‑25, an interaction that is essential for efficient SNARE templating and for generating fusion‑competent trans‑SNARE complexes. The same scaffold stabilizes partially zippered SNARE assemblies at the plasma membrane and is proposed to help maintain vesicles in a primed state, ready for rapid membrane merger once synaptotagmin senses Ca²⁺ and releases the final constraints on fusion. Loss of Munc18‑1 function causes a near‑complete block of synaptic vesicle exocytosis and large dense‑core vesicle release, while graded reductions in Munc18‑1 reduce vesicle docking, cut the size of the readily releasable pool, and impair neurotransmitter output. Heterozygous de novo mutations in STXBP1 that alter Munc18‑1 stability or its interaction with syntaxin‑1 and SNARE complexes are linked to early infantile epileptic encephalopathy and related neurodevelopmental syndromes, where disturbed synaptic vesicle priming and reduced synchronous release correlate with epilepsy, intellectual disability, and movement abnormalities.

References
https://pubmed.ncbi.nlm.nih.gov/33495808/ https://pubmed.ncbi.nlm.nih.gov/20681955/

Protein Size (kDa)	PVDF Transfer Membrane Pore Size (μm)
< 10	0.22
10-20	0.22
20-30	0.45
30-45	0.45
45-70	0.45
80-100	0.45
100-140	0.45
> 140	0.45

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Protein Size (kDa)	Separating Gel Percentage
4-40	20%
12-45	15%
10-70	12.5%
15-100	10%
25-100	8%
60-210	5%

Munc18-1 Antibody (Rabbit mAb) [G23A10]

Usage Information

Experimental Methods

Datasheet & SDS

Biological Description

Tech Support