Expression, synaptic localization, and developmental regulation of Ack1/Pyk1, a cytoplasmic tyrosine kinase highly expressed in the developing and adult brain.
Cytosolic tyrosine kinases play a critical role both in neural development and in adult brain function and plasticity. Here we isolated a cDNA with high homology to human Ack1 and mouse Tnk2. This cDNA directs the expression of a 125-kD protein that can be autophosphorylated in tyrosines. Initially, this clone was named Pyk1 for proline-rich tyrosine kinase (Lev et al., 1995); however, since it corresponds to the mouse homolog of Ack1, here we called it Ack1/Pyk1. In this study we show that Ack1/Pyk1 mRNA and protein is highly expressed in the developing and adult brain. The highest levels of Ack1/Pyk1 expression were detected in the hippocampus, neocortex, and cerebellum. Electron microscopy studies showed that Ack1/Pyk1 protein is expressed in these regions both at dendritic spines and presynaptic axon terminals, indicating a role in synaptic function. Furthermore, we demonstrate that Ack1/Pyk1 mRNA levels are strongly upregulated by increased neural activity, produced by intraperitoneal kainate injections. During development, Ack1/Pyk1 was also expressed in the proliferative ventricular zones and in postmitotic maturing neurons. In neuronal cultures, Ack1/Pyk1 was detected in developing dendrites and axons, including dendritic tips and growth cones. Moreover, Ack1/Pyk1 colocalized with Cdc42 GTPase in neuronal cultures and coimmunoprecipitated with Cdc42 in HEK 293T cells. Altogether, our findings indicate that Ack1/Pyk1 tyrosine kinase may be involved both in adult synaptic function and plasticity and in brain development.
Ureña
Jesús Mariano
JM
Developmental Neurobiology and Regeneration Lab, Institute of Biomedical Research of Barcelona-Parc Científic de Barcelona, University of Barcelona, Josep Samitier 1-5, E08028 Barcelona, Spain. jurena@pcb.ub.es
La Torre
Anna
A
Martínez
Albert
A
Lowenstein
Eve
E
Franco
Neus
N
Winsky-Sommerer
Raphaelle
R
Fontana
Xavier
X
Casaroli-Marano
Ricardo
R
Ibáñez-Sabio
Miguel Angel
MA
Pascual
Marta
M
Del Rio
José Antonio
JA
de Lecea
Luis
L
Soriano
Eduardo
E
D000818:Animals; D000831:Animals, Newborn; D015152:Blotting, Northern / Q000379:methods; D015153:Blotting, Western / Q000379:methods; D001921:Brain / Q000166:cytology / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D002478:Cells, Cultured; D003001:Cloning, Molecular / Q000379:methods; D004622:Embryo, Mammalian; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D047468:Immunoprecipitation / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D007608:Kainic Acid / Q000494:pharmacology; D051379:Mice; D016253:Microscopy, Immunoelectron / Q000379:methods; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D019606:Phosphoamino Acids / Q000378:metabolism; D010766:Phosphorylation; D017729:Presynaptic Terminals / Q000378:metabolism / Q000648:ultrastructure; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D013569:Synapses / Q000378:metabolism* / Q000648:ultrastructure; D013997:Time Factors; D014404:Tubulin / Q000378:metabolism; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism
D018690:Excitatory Amino Acid Agonists; D005904:Glial Fibrillary Acidic Protein; D008869:Microtubule-Associated Proteins; C079240:Mtap2 protein, mouse; D019606:Phosphoamino Acids; D012333:RNA, Messenger; D014404:Tubulin; C462941:beta3 tubulin, mouse; C498594:Tnk2 protein, mouse; D011505:Protein-Tyrosine Kinases; C403262:TNK2 protein, human; D020764:cdc42 GTP-Binding Protein; D007608:Kainic Acid