p116Rip targets myosin phosphatase to the actin cytoskeleton and is essential for RhoA/ROCK-regulated neuritogenesis.
Activation of the RhoA-Rho kinase (ROCK) pathway stimulates actomyosin-driven contractility in many cell systems, largely through ROCK-mediated inhibition of myosin II light chain phosphatase. In neuronal cells, the RhoA-ROCK-actomyosin pathway signals cell rounding, growth cone collapse, and neurite retraction; conversely, inhibition of RhoA/ROCK promotes cell spreading and neurite outgrowth. The actin-binding protein p116(Rip), whose N-terminal region bundles F-actin in vitro, has been implicated in Rho-dependent neurite remodeling; however, its function is largely unknown. Here, we show that p116(Rip), through its C-terminal coiled-coil domain, interacts directly with the C-terminal leucine zipper of the regulatory myosin-binding subunits of myosin II phosphatase, MBS85 and MBS130. RNA interference-induced knockdown of p116(Rip) inhibits cell spreading and neurite outgrowth in response to extracellular cues, without interfering with the regulation of myosin light chain phosphorylation. We conclude that p116(Rip) is essential for neurite outgrowth and may act as a scaffold to target the myosin phosphatase complex to the actin cytoskeleton.
Division of Cellular Biochemistry and Centre for Biomedical Genetics, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands.
Jacqueline
J
Mulder
Aafke
A
Ariaens
Dick
D
van den Boomen
Wouter H
WH
Moolenaar
D000199:Actins / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D003599:Cytoskeleton / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism*; D003902:Detergents / Q000494:pharmacology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008840:Microfilament Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D043263:Myosin-Light-Chain Phosphatase / Q000737:chemistry / Q000378:metabolism*; D016501:Neurites / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D021122:Protein Subunits / Q000378:metabolism; D034622:RNA Interference; D051381:Rats; D012995:Solubility; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D003902:Detergents; D047908:Intracellular Signaling Peptides and Proteins; C498552:MPRIP protein, human; D008840:Microfilament Proteins; D021122:Protein Subunits; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D043263:Myosin-Light-Chain Phosphatase; C500244:Mprip protein, rat; C500243:p116Rip protein, mouse; D020742:rhoA GTP-Binding Protein