β-Arrestins are known to play a crucial role in GPCR-mediated transmembrane signaling processes. However, there are still many unanswered questions, especially those concerning the presumed similarities and differences of β-arrestin isoforms. Here, we examined the roles of β-arrestin 1 and β-arrestin 2 at different levels of μ-opioid receptor (MOR)-regulated signaling, including MOR mobility, internalization of MORs, and adenylyl cyclase (AC) activity. For this purpose, naïve HEK293 cells or HEK293 cells stably expressing YFP-tagged MOR were transfected with appropriate siRNAs to block in a specific way the expression of β-arrestin 1 or β-arrestin 2. We did not find any significant differences in the ability of β-arrestin isoforms to influence the lateral mobility of MORs in the plasma membrane. Using FRAP and line-scan FCS, we observed that knockdown of both β-arrestins similarly increased MOR lateral mobility and diminished the ability of DAMGO and endomorphin-2, respectively, to enhance and slow down receptor diffusion kinetics. However, β-arrestin 1 and β-arrestin 2 diversely affected the process of agonist-induced MOR endocytosis and exhibited distinct modulatory effects on AC function. Knockdown of β-arrestin 1, in contrast to β-arrestin 2, more effectively suppressed forskolin-stimulated AC activity and prevented the ability of activated-MORs to inhibit the enzyme activity. Moreover, we have demonstrated for the first time that β-arrestin 1, and partially β-arrestin 2, may somehow interact with AC and that this interaction is strongly supported by the enzyme activation. These data provide new insights into the functioning of β-arrestin isoforms and their distinct roles in GPCR-mediated signaling.

• Klíčová slova
• Adenylyl cyclase, DAMGO, Endomorphin-2, Receptor lateral mobility, β-Arrestin, μ-Opioid receptor,
• MeSH
• adenylátcyklasy * metabolismus   MeSH
• beta arrestin 1 metabolismus   MeSH
• beta arrestin 2 metabolismus   MeSH
• beta arrestiny metabolismus   MeSH
• HEK293 buňky MeSH
• lidé MeSH
• receptory opiátové mu * metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adenylátcyklasy * MeSH
• ARRB1 protein, human MeSH Prohlížeč
• beta arrestin 1 MeSH
• beta arrestin 2 MeSH
• beta arrestiny MeSH
• receptory opiátové mu * MeSH

The interactions between TRPV1 and µ-opioid receptors (MOR) have recently attracted much attention because these two receptors play important roles in pain pathways and can apparently modulate each other's functioning. However, the knowledge about signaling interactions and crosstalk between these two receptors is still limited. In this study, we investigated the mutual interactions between MOR and TRPV1 shortly after their activation in HEK293 cells expressing these two receptors. After activation of one receptor we observed significant changes in the other receptor's lateral mobility and vice versa. However, the changes in receptor movement within the plasma membrane were not connected with activation of the other receptor. We also observed that plasma membrane β-arrestin 2 levels were altered after treatment with agonists of both these receptors. Knockdown of β-arrestin 2 blocked all changes in the lateral mobility of both receptors. Furthermore, we found that β-arrestin 2 can play an important role in modulating the effectiveness of ERK1/2 phosphorylation after activation of MOR in the presence of TRPV1. These data suggest that β-arrestin 2 and ERK1/2 are important mediators between these two receptors and their signaling pathways. Collectively, MOR and TRPV1 can mutually affect each other's behavior and β-arrestin 2 apparently plays a key role in the bidirectional crosstalk between these two receptors in the plasma membrane.

• Klíčová slova
• ERK1/2, TRPV1, biased signaling, receptor lateral mobility, β-arrestin 2, μ-opioid receptor,
• MeSH
• arrestiny metabolismus   MeSH
• beta arrestin 2 metabolismus   fyziologie   MeSH
• beta arrestiny metabolismus   MeSH
• buněčná membrána metabolismus   fyziologie   MeSH
• fosforylace MeSH
• HEK293 buňky MeSH
• kationtové kanály TRPV metabolismus   fyziologie   MeSH
• lidé MeSH
• MAP kinasový signální systém fyziologie   MeSH
• morfin metabolismus   MeSH
• opioidní analgetika metabolismus   MeSH
• receptory opiátové mu metabolismus   fyziologie   MeSH
• receptory opiátové metabolismus   MeSH
• signální transdukce MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• arrestiny MeSH
• beta arrestin 2 MeSH
• beta arrestiny MeSH
• kationtové kanály TRPV MeSH
• morfin MeSH
• opioidní analgetika MeSH
• receptory opiátové mu MeSH
• receptory opiátové MeSH
• TRPV1 protein, human MeSH Prohlížeč

AT(1) receptor (AT1R) blockade prevents physiological cardiac hypertrophy induced by resistance training. Also, our group showed that a single bout of resistance exercise (RE) activates the AKT/mTOR which was also inhibited by AT1R blocker. Here, we investigated whether IGF1-receptor (IGF1-R) and MAPKs were also activated after a single bout of RE. Wistar rats were divided into Sedentary (Sed), Sedentary treated with losartan (Sed+LOS), Exercise (EX), and Exercise treated with losartan (EX+LOS). Cardiac tissue was obtained 5 and 30 min after 4 sets of 12 repetitions of squat exercise (80 % 1RM). We demonstrated that a single bout of RE did not induce IGF1-R tyrosine phosphorylation. ERK1/2 and P38 phosphorylation levels were elevated in the EX 5min and EX 30min groups however, only ERK1/2 was inhibited by losartan treatment (AT1R blocker). Next, we showed that beta-arrestin-2 expression increased 28 % in trained animals compared to sedentary group. Altogether, our results demonstrate that AT1R, but not IGF1-R, may exert the hypertrophic cardiac stimulus RE-induced. Also, activation of AKT/mTOR and ERK1/2 pathways may occur through the beta-arrestin-dependent pathway.

• MeSH
• beta arrestin 2 metabolismus   MeSH
• blokátory receptorů AT1 pro angiotensin II farmakologie   MeSH
• časové faktory MeSH
• extracelulárním signálem regulované MAP kinasy metabolismus   MeSH
• interakce mezi receptory a ligandy MeSH
• kardiomegalie indukovaná tělesnou námahou * účinky léků   MeSH
• kondiční příprava zvířat metody   MeSH
• losartan farmakologie   MeSH
• myokard metabolismus   MeSH
• odporový trénink * MeSH
• potkani Wistar MeSH
• receptor angiotensinu typ 1 účinky léků   metabolismus   MeSH
• receptor IGF typ 1 metabolismus   MeSH
• signální transdukce * účinky léků   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• Arrb2 protein, rat MeSH Prohlížeč
• beta arrestin 2 MeSH
• blokátory receptorů AT1 pro angiotensin II MeSH
• extracelulárním signálem regulované MAP kinasy MeSH
• losartan MeSH
• receptor angiotensinu typ 1 MeSH
• receptor IGF typ 1 MeSH

Many diseases of the nervous system are accompanied by alterations in synaptic functions. Synaptic plasticity mediated by the endogenous cannabinoid system involves the activation of the cannabinoid receptor 1 (CB1R). The principles of CB1R signaling must be understood in detail for its therapeutic exploration. We detected the Src homology 3-domain growth factor receptor-bound 2-like (endophilin) interacting protein 1 (SGIP1) as a novel CB1R partner. SGIP1 is functionally linked to clathrin-mediated endocytosis and its overexpression in animals leads to an energy regulation imbalance resulting in obesity. We report that SGIP1 prevents the endocytosis of activated CB1R and that it alters signaling via the CB1R in a biased manner. CB1R mediated G-protein activation is selectively influenced by SGIP1, β-arrestin associated signaling is changed profoundly, most likely as a consequence of the prevention of the receptor's internalization elicited by SGIP1.

• Klíčová slova
• Bias signaling, Cannabinoid receptor 1, G-protein coupled receptors, Protein-protein interactions, Receptor endocytosis, Seven transmembrane receptors,
• MeSH
• adaptorové proteiny signální transdukční MeSH
• beta arrestin 2 metabolismus   MeSH
• buněčná membrána účinky léků   metabolismus   MeSH
• endocytóza účinky léků   fyziologie   MeSH
• HEK293 buňky MeSH
• lidé MeSH
• MAP kinasový signální systém fyziologie   MeSH
• mozek metabolismus   MeSH
• myši MeSH
• neurony metabolismus   MeSH
• potkani Wistar MeSH
• receptor kanabinoidní CB1 metabolismus   MeSH
• Saccharomyces cerevisiae MeSH
• techniky dvojhybridového systému MeSH
• transfekce MeSH
• transportní proteiny genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• adaptorové proteiny signální transdukční MeSH
• beta arrestin 2 MeSH
• receptor kanabinoidní CB1 MeSH
• SGIP1 protein, mouse MeSH Prohlížeč
• transportní proteiny MeSH