|Protein Name||Calpain-1 catalytic subunit|
|Milk Fraction||MFGM, Exosome|
|Ref Sequence ID||NP_776684.1|
|Protein Existence Status||Reviewed: Experimental evidence at protein level|
|Protein Function||receptor functioning , activation of enzymes , organization of cytoskeletal proteins , and myofibrillar protein turnover; involved in lysosomal rupture and the resultant release of lysosomal cathepsins into the cytoplasm during neuronal cell death; hydrophobic feature it has an important role in the membrane anchoring; Calpastatin, the ubiquitously expressed endogenous calpain inhibitor, blocks both calpain 1 and 2 with similar efficiency and does not inhibit any other protease|
|Biochemical Properties||family of Ca2+-activated neutral thiol endopeptidases classified as tissue-specific; active at micromolar [Ca2+] concentrations; composed of 80-kDa catalytic subunits, which are products of separate genes, and a 30-kDa regulatory subunit; contains 19 amino acid residues that can be cleaved by autolysis during activation|
|Significance in milk||responsible for mitochondrial and lysosomal membrane permeabilization during mammary gland involution|
|PTMs||Phosphorylation - nine phosphorylated residues were identified in calpain 1|
| Site(s) of PTM(s) |
|Predicted Disorder Regions||NA|
|TM Helix Prediction||No TM helices|
|Bibliography||1. Suzuki, K., Imajoh, S., Emori, Y., Kawasaki, H., Minami, Y., & Ohno, S. (1987). Calcium-activated neutral protease and its endogenous inhibitor. Activation at the cell membrane and biological function. FEBS Letters, 220(2), 271–277. https://doi.org/10.1016/0014-5793(87)80828-1. |
2. Shiraha, H., Glading, A., Chou, J., Jia, Z., & Wells, A. (2002). Activation of m-calpain (calpain II) by epidermal growth factor is limited by protein kinase A phosphorylation of m-calpain. Molecular and Cellular Biology, 22(8), 2716–2727. https://doi.org/10.1128/mcb.22.8.2716-2727.2002.
3. Smith, S. D., Jia, Z., Huynh, K. K., Wells, A., & Elce, J. S. (2003). Glutamate substitutions at a PKA consensus site are consistent with inactivation of calpain by phosphorylation. FEBS Letters, 542(1–3), 115–118. https://doi.org/10.1016/s0014-5793(03)00361-2.
4. Zadran, S., Jourdi, H., Rostamiani, K., Qin, Q., Bi, X., & Baudry, M. (2010). Brain-derived neurotrophic factor and epidermal growth factor activate neuronal m-calpain via mitogen-activated protein kinase-dependent phosphorylation. The Journal of Neuroscience : The Official Journal of the Society for Neuroscience, 30(3), 1086–1095. https://doi.org/10.1523/JNEUROSCI.5120-09.2010.
5. Glading, A., Bodnar, R. J., Reynolds, I. J., Shiraha, H., Satish, L., Potter, D. A., … Wells, A. (2004). Epidermal growth factor activates m-calpain (calpain II), at least in part, by extracellular signal-regulated kinase-mediated phosphorylation. Molecular and Cellular Biology, 24(6), 2499–2512. https://doi.org/10.1128/mcb.24.6.2499-2512.2004.
6. Imajoh, S., Kawasaki, H., & Suzuki, K. (1986). The amino-terminal hydrophobic region of the small subunit of calcium-activated neutral protease (CANP) is essential for its activation by phosphatidylinositol. Journal of Biochemistry, 99(4), 1281–1284. https://doi.org/10.1093/oxfordjournals.jbchem.a135593.
7. Hosfield, C. M. (1999). Crystal structure of calpain reveals the structural basis for Ca2+-dependent protease activity and a novel mode of enzyme activation. The EMBO Journal, 18(24), 6880–6889. https://doi.org/10.1093/emboj/18.24.6880.
8. Strobl, S., Fernandez-Catalan, C., Braun, M., Huber, R., Masumoto, H., Nakagawa, K., … Bode, W. (2000). The crystal structure of calcium-free human m-calpain suggests an electrostatic switch mechanism for activation by calcium. Proceedings of the National Academy of Sciences of the United States of America, 97(2), 588–592. https://doi.org/10.1073/pnas.97.2.588.
9. Ilian, M. A., Gilmour, R. S., & Bickerstaffe, R. (1999). Quantification of ovine and bovine calpain I, calpain II, and calpastatin mRNA by ribonuclease protection assay. Journal of Animal Science, 77(4), 853–864. https://doi.org/10.2527/1999.774853x.
10. Arnandis, T., Ferrer-Vicens, I., García-Trevijano, E. R., Miralles, V. J., García, C., Torres, L., … Zaragozá, R. (2012). Calpains mediate epithelial-cell death during mammary gland involution: mitochondria and lysosomal destabilization. Cell Death and Differentiation, 19(9), 1536–1548. https://doi.org/10.1038/cdd.2012.46.