The axonal localization of large Drosophila ankyrin2 protein isoforms is essential for neuronal functionality.
In polarized cells, such as neurons, ankyrin-type proteins are the major molecules that link the actin-spectrin-based membrane cytoskeleton to the plasma membrane. In Drosophila the second ankyrin gene, Dank2, is exclusively expressed in neuronal cells. Similar to ankyrin genes in other organisms, the Dank2 gene generates several ankyrin protein isoforms by differential splicing. Here we report that in Drosophila, the short Dank2 protein isoform is restricted to neuronal cell bodies and is excluded from axons, whereas the long Dank2 isoforms are localized specifically to axons. Thus the long and short Dank2 protein isoforms are localized to complementary neuronal subdomains, demonstrating that in vivo the composition of the neuronal cortical cytoskeleton is highly polarized. We show that once polarization is established, it persists during later stages of Drosophila development. We also present genetic evidence that the absence of axonal Dank2 protein is lethal.
Hortsch
Michael
M
Department of Cell and Developmental Biology, University of Michigan, Ann Arbor 48109-0616, USA. hortsch@umich.edu
Paisley
Kerry L
KL
Tian
Ming-Zhu
MZ
Qian
Min
M
Bouley
Michael
M
Chandler
Robert
R
D000818:Animals; D017487:Ankyrins / Q000235:genetics / Q000378:metabolism*; D001369:Axons / Q000378:metabolism* / Q000648:ultrastructure; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D016764:Cell Polarity / Q000502:physiology*; D003001:Cloning, Molecular; D003599:Cytoskeleton / Q000378:metabolism*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D005804:Genes, Lethal / Q000235:genetics; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009420:Nervous System / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011679:Pupa / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic / Q000235:genetics
C498993:Ank2 protein, Drosophila; D017487:Ankyrins; D015816:Cell Adhesion Molecules, Neuronal; D029721:Drosophila Proteins; D020033:Protein Isoforms; C061745:Nrg protein, Drosophila