Regulates COPI-mediated retrograde protein traffic at the interface between the Golgi apparatus and the endoplasmic reticulum (PubMed:18556652). Involved in the maintenance of the Golgi apparatus morphology (PubMed:26581903). Has no detectable kinase activity in vitro (PubMed:18556652). Isoform 6 acts as transcriptional activator. It binds to three different types of GC-rich DNA binding sites (box-A, -B and -C) in the beta-polymerase promoter region. It also binds to the TERT promoter region. Interacts with GORAB. Interacts with COPA, COPB1 and COPB2 (By similarity). Homooligomer. Interacts with AP2B1. Localized to the Endoplasmic reticulum-Golgi intermediate and cis-Golgi in an ARF1-independent manner. Cytoplasmic throughout the cell cycle. Cytoplasmic throughout the cell cycle. Cytoplasmic during interphase and centrosomal during mitosis, it localizes to the centrosomes in a microtubule-independent manner. Ubiquitous. The protein kinase domain is predicted to be catalytically inactive. The disease is caused by variants affecting the gene represented in this entry. Non-canonical splice junctions. Belongs to the protein kinase superfamily.