Scaffolding protein that assembles several protein kinases and phosphatases on the centrosome and Golgi apparatus. Required to maintain the integrity of the Golgi apparatus. Required for microtubule nucleation at the cis-side of the Golgi apparatus. Required for association of the centrosomes with the poles of the bipolar mitotic spindle during metaphase. In complex with PDE4DIP, recruits CAMSAP2 to the Golgi apparatus and tethers non-centrosomal minus-end microtubules to the Golgi, an important step for polarized cell movement. In complex with PDE4DIP, EB1/MAPRE1 and CDK5RAP2, contributes to microtubules nucleation and extension also from the centrosome to the cell periphery. The interaction with PDE4DIP is isoform-specific. Interacts with the regulatory region of protein kinase N (PKN), protein phosphatase 2A (PP2A), protein phosphatase 1 (PP1) and the immature non-phosphorylated form of PKC epsilon. Interacts with CIP4 and FNBP1. Interacts with chloride intracellular channel proteins CLIC1, CLIC4 and CLIC5. CSNK1D binding promotes its centrosomal subcellular location. Interacts with GM130/GOLGA2; leading to recruitment to the Golgi apparatus. Interacts with KCNQ1; targets protein kinase A (PKA) catalytic and regulatory subunits and protein phosphatase 1 (PP1), to the heterodimer KCNQ1-KCNE1. Interacts with PDE4DIP; this interaction stabilizes both proteins. In complex with PDE4DIP, recruits CAMSAP2 to the Golgi apparatus. Forms a pericentrosomal complex with CDK5RAP2, EB1/MAPRE1 and PDE4DIP; within this complex, MAPRE1 binding to CDK5RAP2 may be mediated by PDE4DIP. The interaction with PDE4DIP is isoform-specific. Interacts with MAPRE1 and MAPRE3. Interacts (via C-terminus) with CAMSAP2; this interaction is much stronger in the presence of PDE4DIP. Interacts with CAMSAP3. Interacts (via C-terminus) with the gamma-tubulin ring complex (gamma-TuRC), composed of gamma-tubulin, TUBGCP2, TUBGCP3, TUBGCP4, TUBGCP5 and TUBGCP6. Cytoplasmic in parietal cells. Recruited to the Golgi apparatus by GM130/GOLGA2. Localization at the centrosome versus Golgi apparatus may be cell type-dependent. Recruited to the centrosome in the presence of CDK5RAP2. Highly expressed in gastric parietal cells. RII-binding site, predicted to form an amphipathic helix, could participate in protein-protein interactions with a complementary surface on the R-subunit dimer.