Mutations in Drosophila sec15 reveal a function in neuronal targeting for a subset of exocyst components.
The exocyst is a complex of proteins originally identified in yeast that has been implicated in polarized secretion. Components of the exocyst have been implicated in neurite outgrowth, cell polarity, and cell viability. We have isolated an exocyst component, sec15, in a screen for genes required for synaptic specificity. Loss of sec15 causes a targeting defect of photoreceptors that coincides with mislocalization of specific cell adhesion and signaling molecules. Additionally, sec15 mutant neurons fail to localize other exocyst members like Sec5 and Sec8, but not Sec6, to neuronal terminals. However, loss of sec15 does not cause cell lethality in contrast to loss of sec5 or sec6. Our data suggest a role of Sec15 in an exocyst-like subcomplex for the targeting and subcellular distribution of specific proteins. The data also show that functions of other exocyst components persist in the absence of sec15, suggesting that different exocyst components have separable functions.
Mehta
Sunil Q
SQ
Program in Developmental Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
Hiesinger
P Robin
PR
Beronja
Slobodan
S
Zhai
R Grace
RG
Schulze
Karen L
KL
Verstreken
Patrik
P
Cao
Yu
Y
Zhou
Yi
Y
Tepass
Ulrich
U
Crair
Michael C
MC
Bellen
Hugo J
HJ
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D004330:Drosophila / Q000235:genetics*; D005089:Exocytosis / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000235:genetics*; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D009154:Mutation; D009474:Neurons / Q000502:physiology* / Q000648:ultrastructure; D016133:Polymerase Chain Reaction; D021381:Protein Transport / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D013569:Synapses / Q000502:physiology / Q000648:ultrastructure
D008565:Membrane Proteins