Plays an important role in caveolae formation and organization. Essential for the formation of caveolae in all tissues. Core component of the CAVIN complex which is essential for recruitment of the complex to the caveolae in presence of calveolin-1 (CAV1). Essential for normal oligomerization of CAV1. Promotes ribosomal transcriptional activity in response to metabolic challenges in the adipocytes and plays an important role in the formation of the ribosomal transcriptional loop. Dissociates transcription complexes paused by DNA-bound TTF1, thereby releasing both RNA polymerase I and pre-RNA from the template. The caveolae biogenesis pathway is required for the secretion of proteins such as GASK1A. Component of the CAVIN complex composed of CAVIN1, CAVIN2, CAVIN3 and CAVIN4. Interacts with RNA polymerase I and TTF1. Binds the 3' end of pre-rRNA. Interacts with transcription factor ZNF148. Interacts with LIPE in the adipocyte cytoplasm. Interacts with CAV1, CAV3, CAVIN2, CAVIN3 and CAVIN4. Translocates to the cytoplasm from the caveolae upon insulin stimulation (By similarity). Colocalizes with CAV1 in lipid rafts in adipocytes (PubMed:18056712). Localizes in the caveolae in a caveolin-dependent manner (By similarity). Expressed in the adipocyte (at protein level). Expressed in all striated and smooth muscles tested including diaphragm, esophageal striated muscle, fibroblast, endocardial endothelium, epicardial mesothelium, intestinal smooth muscle, masseter, soleus muscle, vascular smooth muscle and white gastrocnemius muscle (at protein level). Expressed in the endothelium and perineural sheath (at protein level). Not expressed in hepatocytes. The leucine-zipper domain 1 is essential for its localization in the caveolae. Phosphorylated. Present in active and inactive forms. Changes in phosphorylation pattern may alter activity. Phosphorylation at Tyr-158 is essential for its function in the regulation of ribosomal transcriptional activity. Monoubiquitinated. Belongs to the CAVIN family.