Cavin3 interacts with cavin1 and caveolin1 to increase surface dynamics of caveolae

Abstract

Caveolae are invaginations of the cell surface thought to regulate membrane tension, signalling, adhesion and lipid homeostasis owing to their dynamic behaviour ranging from stable surface association to dynamic rounds of fission and fusion with the plasma membrane. The caveolae coat is generated by oligomerisation of the membrane protein caveolin and the family of cavin proteins. Here, we show that cavin3 (also known as PRKCDBP) is targeted to caveolae by cavin1 (also known as PTRF) where it interacts with the scaffolding domain of caveolin1 and promote caveolae dynamics. We found that the N-terminal region of cavin3 binds a trimer of the cavin1 N-terminus in competition with a homologous cavin2 (also known as SDPR) region, showing that the cavins form distinct subcomplexes through their N-terminal regions. Our data shows that cavin3 is enriched at deeply invaginated caveolae and that loss of cavin3 in cells results in an increase of stable caveolae and a decrease of caveolae that are only present at the membrane for a short time. We propose that cavin3 is recruited to the caveolae coat by cavin1 to interact with caveolin1 and regulate the duration time of caveolae at the plasma membrane.

Protein kinase C (PKC)-mediated phosphorylation of PACSIN2 triggers the removal of caveolae from the plasma membrane

“…The amount of stably expressed caveolin-1-DsRedm was ∼25% of that of the endogenous caveolin 1 protein, as assessed by western blotting (supplementary material Fig. S1C), which is similar to results in previous functional studies (Mohan et al, 2015). We determined the coordinates of the center of the caveolin-1-DsRedm spots in each time-lapse image, and linked the coordinates of one image to the coordinates of the next image (supplementary material Fig.…”

“…However, recent studies with better time resolution have revealed that the lifetime of caveolae at the plasma membrane is shorter than expected, and varies depending on the cell cycle progression (Boucrot et al, 2011;Mohan et al, 2015). To examine the physiological effect of reduced PACSIN2 membrane binding, we tracked a stably expressing caveolin-1-DsRed-monomer (DsRedm) construct, as a marker of caveolae at the plasma membrane, using TIRF microscopy (Boucrot et al, 2011;Mohan et al, 2015;Pelkmans and Zerial, 2005).…”

“…5). However, the majority of caveolae had tracking durations below 100 s (Boucrot et al, 2011;Mohan et al, 2015) (Fig. 5A,I; supplementary material Movie 1).…”

Human Adipocytes : Proteomic Approaches

“…Cavin-1 is the only one of the cavin proteins necessary for caveolae formation but they all seem to be involved in the membranecurvature formation [75,76]. It is suggested that the cavin proteins form polymerized complexes that line the cytosolic side of caveolae [76][77][78][79].…”

“…Cavin-3 promotes caveolae dynamics [79] and absence of cavin-3 leads to less trafficking of caveolae derived vesicles along microtubules [82]. On the contrary, the caveolae associated protein EH-domain containing protein 2 (EHD2) stabilizes caveolae at the plasma membrane by linking it to actin [83,84].…”