Mouse Monoclonal Antibody to Ubiquitin Cat# MCA-Ubi-1

      Ubiquitin is a globular 76 amino acid protein of about 8.5kDa molecular weight which was discovered by biochemical isolation from bovine thymus tissues (1). The protein was found to be highly conserved in amino acid sequence and was detectable in apparently every cell and tissue type, and, being apparently ubiquitously expressed, became known as ubiquitin. Subsequent work showed that ubiquitin has an important role in the targeting of proteins for proteolytic degradation, but has other important functions (2). Proteins to be degraded are covalently coupled to the C-terminus of ubiquitin as a result of the sequential activity of three families of enzymes, the ubiquitin-activating enzymes (E1s), ubiquitin-conjugating enzymes (E2s), and ubiquitin ligases (E3s). While humans express only two E1 enzymes, there are 35 E2 enzymes and hundreds of E3s. The ubiquitinated protein complex may then be degraded in the proteasome. Ubiquitin becomes covalently bonded to many types of pathological inclusions such as the neurofibrillary tangles of Alzheimer’s disease (3), the Lewy bodies of Parkinson’s disease (4), the Pick bodies of Pick’s disease (5) and many others. Ubiquitin can normally be removed from proteins to which it is bound and reused due to the activity of a large family of deubiquitinating enzymes.

Chromogenic immunostaining of a NBF fixed paraffin embedded human hippocampus section from an Alzheimer’s Disease case. Mouse mAb to ubiquitin, MCA-Ubi-1, dilution 1:2,000, detected with DAB (brown) using the Vector Labs ImmPRESS method and reagents with citra buffer retrieval. Hematoxylin (blue) was used as the counterstain. The MCA-Ubi-1 antibody strongly labels flame shapped tangles in pyramidal neurons and dystrophic neurites nuclei characteristic of Alzheimer's disease. This antibody performs well in testing with 4% PFA or standard NBF fixed human and rat tissues. Mouse select image for larger view.



Blots probed with MCA-Ubi-1 of mono and K48 linked polyubiquitin (Boston Biotech, lane 1), monoubiquitin only (2), and 100μg total wet weight of homogenates of rat cerebellum, cortex and brain stem respectively (lanes 3-5). Material was run out on 20% SDS-PAGE and transferred electrophoretically to PVDF. MCA-Ubi-1 binds both mono and polyubiquitin and detects monoubiquitin in cell and tissue lysates. Mouse select image for larger view.

Additional References;

1. Fortun J, et al. Alterations in degradative pathways and protein aggregation in a neuropathy model based on PMP22 overexpression. Neurobiol Dis. 22:153-164 (2006).
2. Boutajangout A, et al. Characterisation of cytoskeletal abnormalities in mice transgenic for wild-type human tau and familial Alzheimer’s disease mutants of APP and presenilin-1. Neurobiol. Dis. 15:47-60 (2004).
3. Wang DS, et al. Contribution of changes in ubiquitin and myelin basic protein to age-related cognitive decline. Neurosci. Res. 48:93-100 (2004).
4. He CZ, Hays AP. Expression of peripherin in ubiquinated inclusions of amyotrophic lateral sclerosis. J. Neurol. Sci. 217:47-54 (2004).
5. Ungureanu D. et al. Regulation of Jak2 through the ubiquitin-proteasome pathway involves phosphorylation of Jak2 on Y1007 and interaction with SOCS-1. Mol Cell Biol. 22:3316-26 (2002)
6. Wirbelauer C. et al. The F-box protein Skp2 is a ubiquitylation target of a Cul1-based core ubiquitin ligase complex: evidence for a role of Cul1 in the suppression of Skp2 expression in quiescent fibroblasts. EMBO J. 19:5362-75 (2000).
7. Harris KF. et al. Ubiquitin-mediated degradation of active Src tyrosine kinase. Proc Natl Acad Sci U S A. 96:13738-43 (1999).
8. Sternsdorf T, et al. PIC-1/SUMO-1-modified PML-retinoic acid receptor alpha mediates arsenic trioxide-induced apoptosis in acute promyelocytic leukemia. Mol Cell Biol. 19:5170-8 (1999)
9. Marti A, Wirbelauer C, Scheffner M, Krek W. Interaction between ubiquitin-protein ligase SCFSKP2 and E2F-1 underlies the regulation of E2F-1 degradation. Nat Cell Biol. 1:14-9 (1999).

Older peer reviewed publications making use of this antibody.

Perry, G. et al. Proc. Natl. Acad. Sci. USA 84, 3033-3036 (1987)
Shaw, G. and Chau, V. Proc. Natl. Acad. Sci. USA 85, 2854-2858 (1988)
Hirano, S., et al. Cell 70: 293-301 (1992)
Cuervo, A.M., et al. Mol. Biol. 9: 1995-2010 (1995)
Sternsdorf, T., et al. J. Cell Biol. 139: 1621-1634 (1997)
Tae-Wan Kim, et al. J. Biol. Chem. 272: 11006-11010 (1997)
Verdier, F., et al. J. Cell Biol. 273: 28185-28190 (1998)
Laroia, G., et al. Science 284: 499-502 (1999)
Marti, A., et al. Nature Cell Biol. 1: 14-19 (1999)
Sternsdorf, T., et al. Mol. Cell Biol. 19: 5170-5178 (1999)

1. Goldstein G, et al. Isolation of a polypeptide that has lymphocyte-differentiating properties and is probably represented universally in living cells.
PNAS 72:11-5 (1975).
2. Wilkinson K. The discovery of ubiquitin-dependent proteolysis. PNAS 102:15280-2 (2005).
3. Perry G. et al. Ubiquitin is detected in neurofibrillary tangles and senile plaque neurites of Alzheimer disease brains. PNAS 84:3033-6 (1987).
4. Kuzuhara S, et al. Lewy bodies are ubiquitinated. A light and electron microscopic immunocytochemical study. Acta Neuropathol. 75:345-53 (1988).
5. Murayama S. et al. Immunocytochemical and ultrastructural studies of Pick's disease. Ann. Neurol. 27:394-405 (1990).
6. Shaw G. Chau V. Ubiquitin and microtubule-associated protein tau immunoreactivity each define distinct structures with differing distributions and solubility properties in Alzheimer brain. PNAS 85:2854-8 (1988).


This antibody has been widely used for about 30 years, though mostly sold through our OEM partners. Some of the papers which make use of the antibody supplied by EnCor can be found by searching Google Scholar for "MCA-Ubi AND antibody" or, if you are reading this online, go here. For a very recent example of the use of MCA-Ubi-1 on western blots to visualize ubiquitin conjugates go to figure 4e in Gladcova C, et al. Mechanism of parkin activation by PINK1. Nature 559:410-414 (2018).