CAVIN1

This gene encodes a protein that enables the dissociation of paused ternary polymerase I transcription complexes from the 3' end of pre-rRNA transcripts. This protein regulates rRNA transcription by promoting the dissociation of transcription complexes and the reinitiation of polymerase I on nascent rRNA transcripts. This protein also localizes to caveolae at the plasma membrane and is thought to play a critical role in the formation of caveolae and the stabilization of caveolins. This protein translocates from caveolae to the cytoplasm after insulin stimulation. Caveolae contain truncated forms of this protein and may be the site of phosphorylation-dependent proteolysis. This protein is also thought to modify lipid metabolism and insulin-regulated gene expression. Mutations in this gene result in a disorder characterized by generalized lipodystrophy and muscular dystrophy. [provided by RefSeq, Nov 2009]

Full Name

Caveolae Associated Protein 1

Function

Plays an important role in caveolae formation and organization. Essential for the formation of caveolae in all tissues (PubMed:18056712, PubMed:18191225, PubMed:19726876).
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 (By similarity) (PubMed:18056712, PubMed:18191225, PubMed:19726876).
The caveolae biogenesis pathway is required for the secretion of proteins such as GASK1A (By similarity).

Biological Process

Positive regulation of cell motility Source: UniProtKB
Protein secretion Source: Ensembl
rRNA transcription Source: UniProtKB
Termination of RNA polymerase I transcription Source: UniProtKB
Transcription initiation from RNA polymerase I promoter Source: UniProtKB

Cellular Location

Mitochondrion; Microsome; Endoplasmic reticulum; Cytosol; Cell membrane; Nucleus; Caveola. Translocates to the cytoplasm from the caveolae upon insulin stimulation (PubMed:17026959). Colocalizes with CAV1 in lipid rafts in adipocytes. Localizes in the caveolae in a caveolin-dependent manner (By similarity).

Involvement in disease

Congenital generalized lipodystrophy 4 (CGL4): A disorder characterized by the association of congenital generalized lipodystrophy with muscular dystrophy and cardiac anomalies. Congenital generalized lipodystrophy is characterized by a near complete absence of adipose tissue, extreme insulin resistance, hypertriglyceridemia, hepatic steatosis and early onset of diabetes.

PTM

Phosphorylated. Present in active and inactive forms. Changes in phosphorylation pattern may alter activity. Phosphorylation at Tyr-156 is essential for its functionin the regulation of ribosomal transcriptional activity.
Five truncated forms are found in the caveolae. These are thought to be the result of proteolysis and may be phosphorylation-dependent.1 Publication
Monoubiquitinated.