Kinase activity of endosomal kinase LMTK1A regulates its cellular localization and interactions with cytoskeletons.
Neurite formation, a fundamental process in neuronal maturation, requires the coordinated regulation of cytoskeletal reorganization and membrane transport. Compared to the understanding of cytoskeletal functions, less is known about the supply of membranes to growing neurites. Lemur kinase 1A (LMTK1A) is an endosomal protein kinase that is highly expressed in neurons. We recently reported that LMTK1A regulates the trafficking of Rab11-positive recycling endosomes in growing axons and dendrites. Here, we used the kinase-negative (kn) mutant to investigate the role of the kinase activity of LMTK1A in its cellular localization and interactions with the cytoskeleton in Neuro2A and PC-12 cells. Kinase activity was required for the localization of LMTK1A in the perinuclear endocytic recycling compartment. Perinuclear accumulation was microtubule dependent, and LMTK1A wild type (wt) localized mainly on microtubules, whereas kn LMTK1A was found in the actin-rich cell periphery. In the neurites of PC-12 cells, LMTK1A showed contrasting distributions depending on the kinase activity, with wt being located in the microtubule-rich shaft and the kn form in the actin-rich tip. Taken together, these results suggest that the kinase activity of LMTK1A regulates the pathway for endosomal vesicles to transfer from microtubules to actin filaments at the tip of growing neurites.
Laboratory of Molecular Neuroscience, Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, 192-0397, Japan.
Govinda
G
Sharma
Laboratory of Molecular Neuroscience, Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, 192-0397, Japan.
Koji
K
Tsutsumi
Laboratory of Molecular Neuroscience, Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, 192-0397, Japan.
Taro
T
Saito
Laboratory of Molecular Neuroscience, Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, 192-0397, Japan.
Akiko
A
Asada
Laboratory of Molecular Neuroscience, Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, 192-0397, Japan.
Kanae
K
Ando
Integral Education Center, Meikai University, Urayasu, Chiba, 279-9950, Japan.
Mineko
M
Tomomura
Laboratory of Molecular Neuroscience, Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo, 192-0397, Japan. hisanaga-shinichi@tmu.ac.jp.
Shin-Ichi
SI
Hisanaga
D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D002460:Cell Line; D003599:Cytoskeleton / Q000378:metabolism*; D011992:Endosomes / Q000201:enzymology*; D051379:Mice; D008870:Microtubules / Q000378:metabolism; D016501:Neurites / Q000378:metabolism*; D000071446:Neuronal Outgrowth; D016716:PC12 Cells; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D051381:Rats; D014404:Tubulin / Q000378:metabolism
D051017:Apoptosis Regulatory Proteins; D014404:Tubulin; C485554:Aatk protein, mouse; D011505:Protein-Tyrosine Kinases