학술논문
ROCK1 translocates from non-caveolar to caveolar regions upon KCl stimulation in airway smooth muscle
Document Type
TEXT
Author
Source
Physiological research | 2014 Volume:63 | Number:2
Subject
Language
English
Abstract
B. Sommer ... [et al.].
Obsahuje bibliografii a bibliografické odkazy
Airway smooth muscle (ASM) me mbrane depolarization through KCl opens L-type voltage dependent Ca 2+ channels (Ca v 1.2); its opening was considered the caus e of KCl contraction. This substance is used to bypass intracellular second messenger pathways. It is now clear that KCl also activates RhoA/Rho kinase (ROCK) pathway. ROCK isoforms are characterized as ROCK1 and ROCK2. Because ROCK1 seems the most abundant isotype in lung, we studied its participation in KCl stimulated bovine ASM. With methyl- β -cyclodextrin (M β CD) we disrupted caveolae, a membrane compartment considered as the RhoA/ROCK assembly site, and found that KCl contraction was reduced to the same extent (~26 %) as Y-27632 (ROCK inhibitor) treated tissues. We confirmed that KCl induces ROCK activation and this effect was annulled by Y-27632 or M β CD. In isolated plasmalemma, ROCK1 was localized in non-caveolar membrane fractions in Western blots from control tissues, but it transferred to caveolae in samples from tissues stimulated with KCl. Ca v 1.2 was found at the non-caveolar membrane fractions in control and M β CD treated tissues. In M β CD treated tissues stimulated with KCl, contraction was abolished by nifedipine; only the response to Ca v 1.2 opening remained as the ROCK component disappeared. Our result s show that, in ASM, the KCl contraction involves the translocation of ROCK1 from non- caveolar to caveolar regions an d that the proper physiological response depends on this translocation.
Obsahuje bibliografii a bibliografické odkazy
Airway smooth muscle (ASM) me mbrane depolarization through KCl opens L-type voltage dependent Ca 2+ channels (Ca v 1.2); its opening was considered the caus e of KCl contraction. This substance is used to bypass intracellular second messenger pathways. It is now clear that KCl also activates RhoA/Rho kinase (ROCK) pathway. ROCK isoforms are characterized as ROCK1 and ROCK2. Because ROCK1 seems the most abundant isotype in lung, we studied its participation in KCl stimulated bovine ASM. With methyl- β -cyclodextrin (M β CD) we disrupted caveolae, a membrane compartment considered as the RhoA/ROCK assembly site, and found that KCl contraction was reduced to the same extent (~26 %) as Y-27632 (ROCK inhibitor) treated tissues. We confirmed that KCl induces ROCK activation and this effect was annulled by Y-27632 or M β CD. In isolated plasmalemma, ROCK1 was localized in non-caveolar membrane fractions in Western blots from control tissues, but it transferred to caveolae in samples from tissues stimulated with KCl. Ca v 1.2 was found at the non-caveolar membrane fractions in control and M β CD treated tissues. In M β CD treated tissues stimulated with KCl, contraction was abolished by nifedipine; only the response to Ca v 1.2 opening remained as the ROCK component disappeared. Our result s show that, in ASM, the KCl contraction involves the translocation of ROCK1 from non- caveolar to caveolar regions an d that the proper physiological response depends on this translocation.