Arf6 guanine-nucleotide exchange factor, cytohesin-2, interacts with actinin-1 to regulate neurite extension.
Proper regulation of morphological changes in neuronal cells is essential for their differentiation. Complex signaling mechanisms mediate a variety of morphological changes such as formation of neurites. It is well established that a number of small GTPases control neurite behavior before the connection with the target tissue. However, their regulatory mechanisms remain to be fully understood. Here, we show that the Arf6 guanine-nucleotide exchange factor (GEF), cytohesin-2 (CYTH2), interacts with the cytoskeletal protein actinin-1 (ACTN1) and regulates neurite extension in N1E-115 cells used as the model. Knockdown of ACTN1, as well as that of CYTH2, in cells inhibits cellular Arf6 activity and neurite extension. The C-terminal polybasic region of CYTH2 participates in interacting directly with the EFh2 domain of ACTN1. Expression of CYTH2 mutant deficient of the EFh2 domain in cells also inhibits Arf6 activation and neurite extension. Furthermore, FRET analysis detects that the respective interactive region peptides, tagged with cell-permeable short peptides, greatly decrease Arf6 activation at growth cones in a time-dependent manner. Collectively, the signaling through CYTH2 and ACTN1 properly regulates neurite extension in N1E-115 cells, demonstrating the unexpected interaction of CYTH2 and ACTN1 in the regulation of cellular Arf6 activity involved in neurite extension.
Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya, Tokyo 157-8535, Japan.
Tomohiro
T
Torii
Yuki
Y
Miyamoto
Kazuaki
K
Nakamura
Masahiro
M
Maeda
Junji
J
Yamauchi
Akito
A
Tanoue
D000089982:ADP-Ribosylation Factor 6; D020727:ADP-Ribosylation Factors / Q000378:metabolism*; D000185:Actinin / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D020690:GTPase-Activating Proteins / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D016501:Neurites / Q000378:metabolism*; D015398:Signal Transduction
C526905:ACTN1 protein, human; D000089982:ADP-Ribosylation Factor 6; C528567:Actn1 protein, mouse; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; C102474:cytohesin-2; D000185:Actinin; D020727:ADP-Ribosylation Factors; C000715348:ARF6 protein, human; C000715727:Arf6 protein, mouse