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alpha-Smooth Muscle Actin Antibody (4A4)

Catalog # NBP2-22120 | Novus Biologicals a Bio-Techne Brand
Catalog #
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Key Product Details

Species Reactivity

Human, Mouse, Rat, Monkey


ELISA, Flow Cytometry, Immunocytochemistry/ Immunofluorescence, Immunohistochemistry, Immunohistochemistry-Frozen, Immunohistochemistry-Paraffin, Western Blot



Antibody Source

Monoclonal Mouse IgG1 Clone # 4A4


This product is unpurified. The exact concentration of antibody is not quantifiable.

Product Summary for alpha-Smooth Muscle Actin Antibody (4A4)


Alpha-Smooth Muscle Actin Antibody (4A4) is made to a synthesized peptide of human ACTA2.

Reactivity Notes

Mouse blocking reagent may be needed for IHC and ICC experiments to reduce high background signal. You can find these reagents under catalog numbers PK-2200-NB and MP-2400-NB. Please contact Technical Support if you have any questions. Please note that this antibody is reactive to Mouse and derived from the same host, Mouse. Mouse-On-questions.


Mesenchymal Cell Marker







Theoretical MW

42 kDa.
Disclaimer note: The observed molecular weight of the protein may vary from the listed predicted molecular weight due to post translational modifications, post translation cleavages, relative charges, and other experimental factors.

Scientific Data Images for alpha-Smooth Muscle Actin Antibody (4A4)

Immunohistochemistry: alpha-Smooth Muscle Actin Antibody (4A4) [NBP2-22120] - Differential effects of the 20(R/S)-Rg3 stereoisomers on proliferation of VSMCs within plaques. A, Co-immunofluorescence staining of the aortic root for VSMCs (anti-a-SMA antibody, red) and proliferation marker PCNA (green) and DAPI (blue) Scale bar: 20 um. Image collected and cropped by CiteAb from the following publication ( licensed under a CC-BY license.
Immunocytochemistry/Immunofluorescence: alpha-Smooth Muscle Actin Antibody (4A4) [NBP2-22120] - Analysis of HepG2 cells using (green). Red: Actin filaments have been labeled with Alexa Fluor-555 phalloidin. Blue: DRAQ5 fluorescent DNA dye.
Western Blot: alpha-Smooth Muscle Actin Antibody (4A4) [NBP2-22120] - Analysis using alpha-Smooth Muscle Actin Antibody (4A4) against Hela (1), A431 (2), Jurkat (3), K562 (4), HEK293 (5), HepG2 (6), NIH/3T3 (7), PC-12 (8) and Cos7 (9) cell lysate. The theoretical molecular weight of the antibody is 42 kDa.

Applications for alpha-Smooth Muscle Actin Antibody (4A4)

Recommended Usage



Flow Cytometry

1:200 - 1:400

Immunocytochemistry/ Immunofluorescence

1:200 - 1:1000


1:200 - 1:1000


1:200 - 1:1000

Western Blot

1:500 - 1:2000
Application Notes
alpha-Smooth Muscle Actin antibody validated for IHC-Frozen from a verified customer review.
Please Note: Optimal dilutions of this antibody should be experimentally determined.

Reviewed Applications

Read 1 review rated 5 using NBP2-22120 in the following applications:

Published Applications

Read 8 publications using NBP2-22120 in the following applications:

Formulation, Preparation, and Storage






0.03% Sodium Azide


This product is unpurified. The exact concentration of antibody is not quantifiable.


The product is shipped with polar packs. Upon receipt, store it immediately at the temperature recommended below.

Stability & Storage

Store at 4C short term. Aliquot and store at -20C long term. Avoid freeze-thaw cycles.

Background: alpha-Smooth Muscle Actin

Actin proteins are highly conserved in eukaryotic cells and are involved in cell motility, structure and integrity. Actin and myosin are involved in a myriad of cellular processes including locomotion, secretion, cytoplasmic streaming, phagocytosis and cytokinesis. Actin filaments, along with microtubules, comprise a major component of the cytoskeleton and play essential roles in regulating cell shape and movement. Actin has been found to be expressed in at least six isoforms, each encoded by a separate gene and expressed in a developmentally regulated and tissue-specific manner. Alpha, beta and gamma actin isoforms have been identified. Alpha actins are a major constituent of the contractile apparatus, whereas beta and gamma actins are involved in the regulation of cell motility.

ACTA2 encodes alpha Smooth Muscle Actin and is also known as alpha-actin, alpha-actin-2, aortic smooth muscle or alpha smooth muscle actin (alpha-SMA, SMactin, alpha-SM-actin, ASMA). Alpha Smooth Muscle Actin is frequently used as a marker of smooth muscle differentiation and has a theoretical molecular weight of 42 kDa. Smooth muscle alpha actin is one of a few genes whose expression is predominantly expressed in vascular smooth muscle cells that is used to study myofibroblasts and fibrosis (1). Excessive accumulation of alpha smooth muscle actin-positive (ACTA2+) activated myofibroblasts is observed in Idiopathic pulmonary fibrosis (2). Expression of smooth muscle alpha actin is regulated by cell proliferation and is altered in pathological conditions including atherosclerosis and is common in metastatic cancers (1,3).


1. Chakraborty, R., Saddouk, F. Z., Carrao, A. C., Krause, D. S., Greif, D. M., & Martin, K. A. (2019). Promoters to Study Vascular Smooth Muscle. Arterioscler Thromb Vasc Biol, 39(4), 603-612. doi:10.1161/atvbaha.119.312449

2 .El Agha, E., Moiseenko, A., Kheirollahi, V., De Langhe, S., Crnkovic, S., Kwapiszewska, G., . . . Bellusci, S. (2017). Two-Way Conversion between Lipogenic and Myogenic Fibroblastic Phenotypes Marks the Progression and Resolution of Lung Fibrosis. Cell Stem Cell, 20(2), 261-273.e263. doi:10.1016/j.stem.2016.10.004

3. Chen, Y. C., Gonzalez, M. E., Burman, B., Zhao, X., Anwar, T., Tran, M., . . . Kleer, C. G. (2019). Mesenchymal Stem/Stromal Cell Engulfment Reveals Metastatic Advantage in Breast Cancer. Cell Rep, 27(13), 3916-3926.e3915. doi:10.1016/j.celrep.2019.05.084

Long Name

Actin, Alpha 2, Smooth Muscle, Aorta

Alternate Names

AAT6, ACTA2, Actin alpha 2, ACTSA, ACTVS, alphaSmooth Muscle Actin, MYMY5, SMA

Entrez Gene IDs

59 (Human)

Gene Symbol



Product Documents for alpha-Smooth Muscle Actin Antibody (4A4)

Certificate of Analysis

To download a Certificate of Analysis, please enter a lot number in the search box below.

Product Specific Notices for alpha-Smooth Muscle Actin Antibody (4A4)

This product is for research use only and is not approved for use in humans or in clinical diagnosis. Primary Antibodies are guaranteed for 1 year from date of receipt.


FAQs for alpha-Smooth Muscle Actin Antibody (4A4)

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  • Q: Which antibodies would you recommend for the best performance in IHC?

    A: NB300-978, NBP1-30894, NBP2-22120, NBP2-32808, NBP2-33006, and NBP2-34522 have the broadest IHC applications, as they additionally list IHC-Paraffin and IHC-Frozen. To narrow the list down further, we would recommend using either NB300-978 or NBP2-33006 since these products have the most ratings and cited publications for use in IHC methods. NB300-978 has IHC-Free-Floating listed as an application as well.

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