Marlin-1 and conventional kinesin link GABAB receptors to the cytoskeleton and regulate receptor transport.
The cytoskeleton and cytoskeletal motors play a fundamental role in neurotransmitter receptor trafficking, but proteins that link GABA(B) receptors (GABA(B)Rs) to the cytoskeleton have not been described. We recently identified Marlin-1, a protein that interacts with GABA(B)R1. Here, we explore the association of GABA(B)Rs and Marlin-1 to the cytoskeleton using a combination of biochemistry, microscopy and live cell imaging. Our results indicate that Marlin-1 is associated to microtubules and the molecular motor kinesin-I. We demonstrate that a fraction of Marlin-1 is mobile in dendrites of cultured hippocampal neurons and that mobility is microtubule-dependent. We also show that GABA(B)Rs interact robustly with kinesin-I and that intracellular membranes containing GABA(B)Rs are sensitive to treatments that disrupt a protein complex containing Marlin-1, kinesin-I and tubulin. Finally, we report that a kinesin-I mutant severely impairs receptor transport. We conclude that Marlin-1 and kinesin-1 link GABA(B)Rs to the tubulin cytoskeleton in neurons.
Vidal
René L
RL
Physiology and Biophysics, ICBM, Faculty of Medicine, Universidad de Chile Independencia 1027, Santiago, Chile.
Ramírez
Omar A
OA
Sandoval
Lisette
L
Koenig-Robert
Roger
R
Härtel
Steffen
S
Couve
Andrés
A
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000502:physiology*; D004622:Embryo, Mammalian; D005260:Female; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology; D016547:Kinesins / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D015739:Nocodazole / Q000494:pharmacology; D011247:Pregnancy; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D016601:RNA-Binding Proteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018079:Receptors, GABA / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection
D000970:Antineoplastic Agents; C484853:Jakmip1 protein, rat; D016601:RNA-Binding Proteins; D018079:Receptors, GABA; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D016547:Kinesins; D015739:Nocodazole