Kinesin-1 and mitochondrial motility control by discrimination of structurally equivalent but distinct subdomains in Ran-GTP-binding domains of Ran-binding protein 2.
Abstract
The pleckstrin homology (PH) domain is a versatile fold that mediates a variety of
protein-protein and protein-phosphatidylinositol lipid interactions. The Ran-binding
protein 2 (RanBP2) contains four interspersed Ran GTPase-binding domains (RBD(n =
1-4)) with close structural homology to the PH domain of Bruton's tyrosine kinase.
The RBD2, kinesin-binding domain (KBD) and RBD3 comprise a tripartite domain (R2KR3)
of RanBP2 that causes the unfolding, microtubule binding and biphasic activation of
kinesin-1, a crucial anterograde motor of mitochondrial motility. However, the interplay
between Ran GTPase and R2KR3 of RanBP2 in kinesin-1 activation and mitochondrial motility
is elusive. We use structure-function, biochemical, kinetic and cell-based assays
with time-lapse live-cell microscopy of over 260,000 mitochondrial-motility-related
events to find mutually exclusive subdomains in RBD2 and RBD3 towards Ran GTPase binding,
kinesin-1 activation and mitochondrial motility regulation. The RBD2 and RBD3 exhibit
Ran-GTP-independent, subdomain and stereochemical-dependent discrimination on the
biphasic kinetics of kinesin-1 activation or regulation of mitochondrial motility.
Further, KBD alone and R2KR3 stimulate and suppress, respectively, multiple biophysical
parameters of mitochondrial motility. The regulation of the bidirectional transport
of mitochondria by either KBD or R2KR3 is highly coordinated, because their kinetic
effects are accompanied always by changes in mitochondrial motile events of either
transport polarity. These studies uncover novel roles in Ran GTPase-independent subdomains
of RBD2 and RBD3, and KBD of RanBP2, that confer antagonizing and multi-modal mechanisms
of kinesin-1 activation and regulation of mitochondrial motility. These findings open
new venues towards the pharmacological harnessing of cooperative and competitive mechanisms
regulating kinesins, RanBP2 or mitochondrial motility in disparate human disorders.
Type
Journal articleSubject
AnimalsHumans
Kinesin
Kinetics
Mice
Mitochondria
Molecular Chaperones
NIH 3T3 Cells
Nuclear Pore Complex Proteins
Protein Binding
Protein Structure, Tertiary
Up-Regulation
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https://hdl.handle.net/10161/15576Published Version (Please cite this version)
10.1098/rsob.120183Publication Info
Patil, Hemangi; Cho, Kyoung-in; Lee, James; Yang, Yi; Orry, Andrew; & Ferreira, Paulo
A (2013). Kinesin-1 and mitochondrial motility control by discrimination of structurally equivalent
but distinct subdomains in Ran-GTP-binding domains of Ran-binding protein 2. Open Biol, 3(3). pp. 120183. 10.1098/rsob.120183. Retrieved from https://hdl.handle.net/10161/15576.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Paulo Alexandre Ferreira
Associate Professor in Ophthalmology
The long-term goal of our research program is twofold. The first is to understand
the interplay between intracellular signaling, intracellular trafficking and proteostasis in
health and disease; the second is to uncover molecular players and mechanisms partaking
in such processes that are amenable to therapeutic intervention in a variety of disease
states. Presently, our research efforts are centered on dissecting the roles of two
disease-associated protein interactomes assembled by the Ran

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