The Journal of Neuroscience, December 1, 2000, 20(23):8551-8565
Neurobeachin: A Protein Kinase A-Anchoring,
beige/Chediak-Higashi Protein Homolog Implicated in
Neuronal Membrane Traffic
Xiaolu
Wang1,
Friedrich
W.
Herberg1,
Michael M.
Laue1,
Christiane
Wüllner1,
Bin
Hu1,
Elisabeth
Petrasch-Parwez2, and
Manfred W.
Kilimann1
1 Institut für Physiologische Chemie and
2 Institut für Anatomie, Ruhr-Universität
Bochum, D-44780 Bochum, Germany
We describe the identification and initial characterization of
neurobeachin, a neuron-specific multidomain protein of 327 kDa with a
high-affinity binding site (Kd, 10 nM) for the type II regulatory subunit of protein kinase A
(PKA RII). Neurobeachin is peripherally associated with
pleomorphic tubulovesicular endomembranes near the trans
sides of Golgi stacks and throughout the cell body and cell processes.
It is also found in a subpopulation of synapses, where it is
concentrated at the postsynaptic plasma membrane. In live cells,
perinuclear neurobeachin is dispersed by brefeldin A (BFA) within 1 min, and in permeabilized cells a recruitment of neurobeachin from
cytosol to Golgi-near membranes is stimulated by GTP
S and prevented
by brefeldin A. Spots of neurobeachin recruitment are close to but
distinct from recruitment sites of COP-I, AP-1, and AP-3 coat proteins
involved in vesicle budding. These observations indicate that
neurobeachin binding to membranes close to the
trans-Golgi requires an ADP-ribosylation factor-like
GTPase, possibly in association with a novel type of protein coat. A
neurobeachin isoform that does not bind RII, beige-like protein (BGL),
is expressed in many tissues. Neurobeachin, BGL, and ~10 other
mammalian gene products share a characteristic C-terminal BEACH-WD40
sequence module, which is also present in gene products of
invertebrates, plants, protozoans, and yeasts, thus defining a new
protein family. The prototype member of this family of BEACH domain
proteins, lysosomal trafficking regulator (LYST), is deficient in
genetic defects of protein sorting in lysosome biogenesis (the
beige mouse and Chediak-Higashi syndrome).
Neurobeachin's subcellular localization, its coat protein-like
membrane recruitment, and its sequence similarity to LYST suggest an
involvement in neuronal post-Golgi membrane traffic, one of its
functions being to recruit protein kinase A to the membranes with which
it associates.
Key words:
AKAP; ARF; BEACH domain; BGL; coat protein; Golgi
complex; LYST; membrane traffic; neurobeachin; protein kinase A; scaffolding protein; synapse; TGN
Copyright © 2000 Society for Neuroscience 0270-6474/00/20238551-15$05.00/0