Endocytosis of microperoxidase in marginal cells is mainly regulated by RhoA signaling cascade, but not by Rho-associated protein kinase, myosin light-chain kinase and myosin phosphatase.
Endocytosis plays an important role in cell function and the activation and propagation of signaling pathways. Signaling occurs on endocytic pathways and signaling endosomes, and endocytosis is subjected to high-order regulation by cellular signaling mechanisms. Marginal cells showed active endocytosis of microperoxidase (MPO) via the clathrin-independent pathway. We examined the signaling pathway that regulates MPO endocytosis in marginal cells using specific inhibitors and activators of signaling molecules. The results showed that pertussis toxin - which inhibits the ribosylation of G-protein-coupled receptor - did not affect MPO endocytosis, but Clostridium botulinum C3 toxin - which induces RhoA inactivation resulting in extracellular-signal-related kinase inactivation - inhibited MPO endocytosis. The main endocytotic pathway of MPO did not depend on the Rho-associated protein kinase molecular switch or actin/myosin motor system, but was mainly regulated by the RhoA signaling cascade.
Department of Otolaryngology, Faculty of Medicine, University of Tokyo, Tokyo, Japan. kakigi-tky@umin.ac.jp
Akinobu
A
Kakigi
Teruhiko
T
Okada
Taizo
T
Takeda
Setsuko
S
Takeda
Rie
R
Nishioka
Daizo
D
Taguchi
Masahiko
M
Nishimura
Tatsuya
T
Yamasoba
D036002:ADP Ribose Transferases / Q000494:pharmacology; D000818:Animals; D001905:Botulinum Toxins / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D003053:Cochlear Duct / Q000166:cytology / Q000201:enzymology*; D004705:Endocytosis / Q000502:physiology; D004710:Endolymph / Q000378:metabolism; D006168:Guinea Pigs; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism*; D043263:Myosin-Light-Chain Phosphatase / Q000378:metabolism*; D010544:Peroxidases / Q000378:metabolism*; D037342:Pertussis Toxin / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D054460:rho-Associated Kinases / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
D010544:Peroxidases; C021799:microperoxidase; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D037342:Pertussis Toxin; D054460:rho-Associated Kinases; D009219:Myosin-Light-Chain Kinase; D043263:Myosin-Light-Chain Phosphatase; D001905:Botulinum Toxins; D020742:rhoA GTP-Binding Protein