Peptides Interfering with Direct AKAPMediated Protein Protein Interactions

Disruption of AKAP-PKA interactions with PKA-anchoring disruptor peptides has provided insight into the function of this interaction. Inactive PKA holoen-zyme is a heterotetramer consisting of a homodimer of regulatory RI (RIa or RIß) or RII (Rila or RIIß) subunits and two catalytic (Ca, Cß or Cy) subunits, each bound to one of the regulatory subunits (Kim et al. 2007; Wu et al. 2007). Depending on the presence of RI or RII subunits, PKA is designated type I or type II. AKAPs bind dimers of regulatory subunits, preferentially RII subunits, although some AKAPs also bind RI subunits. The PKA-binding domains of AKAPs (also termed RII-binding domains) are structurally conserved. They form amphipathic a-helices, which dock into a hydrophobic pocket formed by the R subunits dimers, the dimerisation and docking (DD) domain. The identity of amino acid sequences of RII-binding domains is <30%. The amphipathic helix

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