MyRIP Anchors Protein Kinase A to the Exocyst Complex

• Published in: The Journal of biological chemistry 2007-11, Vol.282 (45), p.33155-33167
• Main Authors: Goehring, April S., Pedroja, Benjamin S., Hinke, Simon A., Langeberg, Lorene K., Scott, John D.
• Format: Article
• Language: English
• Subjects: A Kinase Anchor Proteins - chemistry; A Kinase Anchor Proteins - genetics; A Kinase Anchor Proteins - metabolism; Amino Acid Sequence; Animals; Binding Sites; Cell Line; Cyclic AMP-Dependent Protein Kinases - classification; Cyclic AMP-Dependent Protein Kinases - genetics; Cyclic AMP-Dependent Protein Kinases - metabolism; Humans; Mice; Molecular Sequence Data; Protein Binding; Sequence Alignment; Sequence Homology, Amino Acid; Vesicular Transport Proteins - chemistry; Vesicular Transport Proteins - genetics; Vesicular Transport Proteins - metabolism; Zebrafish; Zebrafish Proteins - chemistry; Zebrafish Proteins - genetics; Zebrafish Proteins - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M705167200

The movement of signal transduction enzymes in and out of multi-protein complexes coordinates the spatial and temporal resolution of cellular events. Anchoring and scaffolding proteins are key to this process because they sequester protein kinases and phosphatases with a subset of their preferred substrates. The protein kinase A-anchoring family of proteins (AKAPs), which target the cAMP-dependent protein kinase (PKA) and other enzymes to defined subcellular microenvironments, represent a well studied group of these signal-organizing molecules. In this report we demonstrate that the Rab27a GTPase effector protein MyRIP is a member of the AKAP family. The zebrafish homolog of MyRIP (Ze-AKAP2) was initially detected in a two-hybrid screen for AKAPs. A combination of biochemical, cell-based, and immunofluorescence approaches demonstrate that the mouse MyRIP ortholog targets the type II PKA holoenzyme via an atypical mechanism to a specific perinuclear region of insulin-secreting cells. Similar approaches show that MyRIP interacts with the Sec6 and Sec8 components of the exocyst complex, an evolutionarily conserved protein unit that controls protein trafficking and exocytosis. These data indicate that MyRIP functions as a scaffolding protein that links PKA to components of the exocytosis machinery.