Scaffolding protein that assembles several protein kinases and phosphatases on the centrosome and Golgi apparatus. Required to maintain the integrity of the Golgi apparatus (PubMed:10202149, PubMed:15047863). Required for microtubule nucleation at the cis-side of the Golgi apparatus (PubMed:15047863, PubMed:19242490). Required for association of the centrosomes with the poles of the bipolar mitotic spindle during metaphase (PubMed:25657325). In complex with PDE4DIP isoform 13/MMG8/SMYLE, recruits CAMSAP2 to the Golgi apparatus and tethers non-centrosomal minus-end microtubules to the Golgi, an important step for polarized cell movement (PubMed:27666745, PubMed:28814570). In complex with PDE4DIP isoform 13/MMG8/SMYLE, EB1/MAPRE1 and CDK5RAP2, contributes to microtubules nucleation and extension also from the centrosome to the cell periphery (PubMed:29162697). Associated with the N-methyl-D-aspartate receptor and is specifically found in the neuromuscular junction (NMJ) as well as in neuronal synapses, suggesting a role in the organization of postsynaptic specializations. 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 (PubMed:15047863). Interacts with chloride intracellular channel proteins CLIC1, CLIC4 and CLIC5 (PubMed:12163479). CSNK1D binding promotes its centrosomal subcellular location (PubMed:12270714). Interacts with GM130/GOLGA2; leading to recruitment to the Golgi apparatus (PubMed:19242490). Interacts with KCNQ1; targets protein kinase A (PKA) catalytic and regulatory subunits and protein phosphatase 1 (PP1), to the heterodimer KCNQ1-KCNE1 (PubMed:11799244). Interacts with PDE4DIP isoform 13/MMG8/SMYLE; this interaction stabilizes both proteins (PubMed:25217626, PubMed:27666745, PubMed:28814570). In complex with PDE4DIP isoform 13, recruits CAMSAP2 to the Golgi apparatus (PubMed:27666745, PubMed:28814570). Forms a pericentrosomal complex with CDK5RAP2, EB1/MAPRE1 and PDE4DIP isoform 13; within this complex, MAPRE1 binding to CDK5RAP2 may be mediated by PDE4DIP (PubMed:29162697). Interacts with MAPRE1 and MAPRE3 (PubMed:28814570). Interacts (via C-terminus) with CAMSAP2; this interaction is much stronger in the presence of PDE4DIP isoform 13/MMG8/SMYLE (PubMed:27666745). Interacts with CAMSAP3 (PubMed:28089391). Interacts (via C-terminus) with the gamma-tubulin ring complex (gamma-TuRC), composed of gamma-tubulin, TUBGCP2, TUBGCP3, TUBGCP4, TUBGCP5 and TUBGCP6 (PubMed:27666745). Cytoplasmic in parietal cells (PubMed:9915845). Recruited to the Golgi apparatus by GM130/GOLGA2 (PubMed:25657325). Localization at the centrosome versus Golgi apparatus may be cell line-dependent. In SKBr3 and HEK293F cells, exclusively located at the centrosome (PubMed:29162697). In HeLa, MDA-MB231 and RPE-1 cells, detected at the Golgi apparatus (PubMed:25217626, PubMed:29162697). In SK-BR-3 cells, recruited to the centrosome in the presence of CDK5RAP2 (PubMed:29162697). Widely expressed (PubMed:10202149). Isoform 4: Highly expressed in skeletal muscle and in pancreas (PubMed:9482789). RII-binding site, predicted to form an amphipathic helix, could participate in protein-protein interactions with a complementary surface on the R-subunit dimer. The disease is caused by variants affecting the gene represented in this entry.