Cell Signaling Technology

Product Pathways - Apoptosis

PathScan® Total SQSTM1/p62 Sandwich ELISA Kit #7814

When ordering five or more kits, please contact us for processing time and pricing at sales@cellsignal.com.

Kit Includes Volume Solution Color
SQSTM1/p62 Rabbit Antibody coated microwells 96 tests
SQSTM1/p62 Mouse Detection Antibody 11 ml Green
Anti-mouse IgG, HRP-linked Antibody 11 ml Red
TMB Substrate #7004 11 ml Colorless
STOP Solution #7002 11 ml Colorless
Sealing Tape 2 sheets
ELISA Wash Buffer (20X) 25 ml Colorless
ELISA Sample Diluent 25 ml Blue
Cell Lysis Buffer (10X) #9803 15 ml Yellowish

Note: 12 8-well modules –Each module is designed to break apart for 8 tests.
Note: Kit should be stored at 4°C with the exception of Cell Lysis Buffer, which is stored at –20°C (packaged separately).

Species Cross-Reactivity

H M R Mk Mi

Reactivity Key:  H=Human  M=Mouse  R=Rat  Mk=Monkey  Mi=Mink
Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Description

The PathScan® Total SQSTM1/p62 Sandwich ELISA Kit is a solid phase sandwich enzyme-linked immunosorbent assay (ELISA) that detects endogenous levels of total SQSTM1/p62 protein. An SQSTM1/p62 Rabbit Antibody has been coated onto the microwells. After incubation with cell lysates, SQSTM1/p62 protein is captured by the coated antibody. Following extensive washing, SQSTM1/p62 Mouse Detection Antibody is added to detect the captured SQSTM1/p62 protein. Anti-Mouse IgG, HRP-linked Antibody is then used to recognize the bound detection antibody. HRP substrate, TMB, is added to develop color. The magnitude of absorbance for this developed color is proportional to the quantity of total SQSTM1/p62 protein.Antibodies in kit are custom formulations specific to kit.

Specificity / Sensitivity

PathScan® Total SQSTM1/p62 Sandwich ELISA Kit detects endogenous levels of SQSTM1/p62 protein in human cells as shown in Figure 1. The kit sensitivity is shown in Figure 2. This kit detects proteins from the indicated species, as determined through in-house testing, but may also detect homologous proteins from other species.

ELISA - Western correlation

ELISA - Western correlation

Figure 1. SQSTM1/p62 protein from SK-MEL-2 cells is detected using PathScan® Total SQSTM1/p62 Sandwich ELISA Kit #7814. This kit detects lower levels of SQSTM1/p62 in SK-MEL-2 cells starved overnight in Earle's Balanced Salt Solution (EBSS). The absorbance readings at 450 nm are shown in the top figure, while the corresponding western blot using SQSTM1/p62 (D5E2) Rabbit mAb #8025 is shown in the bottom figure.

Sensitivity

Sensitivity

Figure 2. The relationship between protein concentration of lysates from unstarved and EBSS-starved SK-MEL-2 cells and the absorbance at 450 nm is shown. SK-MEL-2 cells (85% confluence) were starved overnight in EBSS at 37ºC and then lysed.

Background

Sequestosome 1 (SQSTM1, p62) is a ubiquitin binding protein involved in cell signaling, oxidative stress, and autophagy (1-4). It was first identified as a protein that binds to the SH2 domain of p56Lck (5), and independently found to interact with PKCζ (6,7). SQSTM1 was subsequently found to interact with ubiquitin, providing a scaffold for several signaling proteins and triggering degradation of proteins through the proteasome or lysosome (8). Interaction between SQSTM1 and TRAF6 leads to the K63-linked polyubiquitination of TRAF6 and subsequent activation of the NF-κB pathway (9). Protein aggregates formed by SQSTM1 can be degraded by the autophagosome (4,10,11). SQSTM1 binds autophagosomal membrane protein LC3/Atg8, bringing SQSTM1-containing protein aggregates to the autophagosome (12). Lysosomal degradation of autophagosomes leads to a decrease in SQSTM1 levels during autophagy; conversely, autophagy inhibitors stabilize SQSTM1 levels. Studies have demonstrated a link between SQSTM1 and oxidative stress. SQSTM1 interacts with KEAP1, which is a cytoplasmic inhibitor of NRF2, a key transcription factor involved in cellular responses to oxidative stress (3). Thus, accumulation of SQSTM1 can lead to an increase in NRF2 activity.

  1. Kirkin, V. et al. (2009) Mol Cell 34, 259-69.
  2. Seibenhener, M.L. et al. (2007) FEBS Lett 581, 175-9.
  3. Komatsu, M. et al. (2010) Nat Cell Biol 12, 213-23.
  4. Bjørkøy, G. et al. (2006) Autophagy 2, 138-9.
  5. Joung, I. et al. (1996) Proc Natl Acad Sci USA 93, 5991-5.
  6. Sanchez, P. et al. (1998) Mol Cell Biol 18, 3069-80.
  7. Puls, A. et al. (1997) Proc Natl Acad Sci USA 94, 6191-6.
  8. Vadlamudi, R.K. et al. (1996) J Biol Chem 271, 20235-7.
  9. Wooten, M.W. et al. (2005) J Biol Chem 280, 35625-9.
  10. Bjørkøy, G. et al. (2005) J Cell Biol 171, 603-14.
  11. Komatsu, M. et al. (2007) Cell 131, 1149-63.
  12. Pankiv, S. et al. (2007) J Biol Chem 282, 24131-45.

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