Regulation of dendrite growth and maintenance by exocytosis.
Dendrites lengthen by several orders of magnitude during neuronal development, but how membrane is allocated in dendrites to facilitate this growth remains unclear. Here, we report that Ras opposite (Rop), the Drosophila ortholog of the key exocytosis regulator Munc18-1 (also known as STXBP1), is an essential factor mediating dendrite growth. Neurons with depleted Rop function exhibit reduced terminal dendrite outgrowth followed by primary dendrite degeneration, suggestive of differential requirements for exocytosis in the growth and maintenance of different dendritic compartments. Rop promotes dendrite growth together with the exocyst, an octameric protein complex involved in tethering vesicles to the plasma membrane, with Rop-exocyst complexes and exocytosis predominating in primary dendrites over terminal dendrites. By contrast, membrane-associated proteins readily diffuse from primary dendrites into terminals, but not in the reverse direction, suggesting that diffusion, rather than targeted exocytosis, supplies membranous material for terminal dendritic growth, revealing key differences in the distribution of materials to these expanding dendritic compartments.
Department of Biology, University of Washington, Seattle, WA 98195, USA.
Yun
Y
Peng
Department of Biology, University of Washington, Seattle, WA 98195, USA.
Jiae
J
Lee
Department of Molecular and Cellular Pharmacology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
Kimberly
K
Rowland
Department of Molecular and Cellular Pharmacology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
Yuhui
Y
Wen
Department of Molecular and Cellular Pharmacology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
Hope
H
Hua
Department of Molecular and Cellular Pharmacology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
Nicole
N
Carlson
Department of Molecular and Cellular Pharmacology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
Shweta
S
Lavania
Department of Biology, University of Washington, Seattle, WA 98195, USA jzp2@uw.edu mkim2@med.miami.edu.
Jay Z
JZ
Parrish
Department of Molecular and Cellular Pharmacology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA jzp2@uw.edu mkim2@med.miami.edu.
Michael D
MD
Kim
D000818:Animals; D002460:Cell Line; D003712:Dendrites / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster; D005089:Exocytosis; D051938:Munc18 Proteins / Q000235:genetics / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*
D029721:Drosophila Proteins; D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins; C086393:Rop protein, Drosophila
Dendrite; Drosophila; Exocyst; Munc18-1; Neurodegeneration; STXBP1