Role of COP9 signalosome subunit 3 (CSN3) phosphorylation in integrin-mediated cardiac hypertrophy
AuthorTeh, Denise Nicole E.
Biochemistry & Molecular Biology
Biochem and Molecular Biology
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Integrins are involved in various aspects of cell regulation, signaling, and growth and have been shown to react to environmental stimuli such as mechanical stress in cardiac myocytes. These integrin-mediated reactions may be linked to the upregulation of hypertrophic genes that result in cardiac hypertrophy, which is the focus of our lab. CSN is a highly conserved complex involved in cell regulation and a critical component to cell differentiation. Previous research has shown that the third subunit of the COP9 signalosome (CSN3) complex binds specifically to ß1D integrin, an isoform that is predominant in adult striated muscle. CSN3 is phosphorylated on serine residues 410, 421 and 423; however the role of these phosphorylation sites remains to be determined. Therefore, we hypothesize that phosphorylation at one or a combination of these sites results in the physical disassociation of CSN3 from ß1D integrin upon integrin activation. To test this hypothesis, CSN3 serine residues 410, 421 and 423 were mutated to either Alanine (to prevent phosphorylation) or Aspartic Acid (to mimic phosphorylation). The following techniques were utilized in this experiment: polymerase chain reaction (PCR), gel electrophoresis and DNA purification. All constructs were confirmed to contain both the pShuttle-IRES-hrGFP-1 vector and the CSN3 gene with the desired mutations via DNA sequencing.