| Name: |
| Douglas G. Cole |
| Title: |
| Interim Department Chair and Associate Professor |
| Degree: |
| Ph.D., 1990, Washington State University |
| Phone: |
| (208) 885-4071 |
| Fax: |
| (208) 885-6518 |
| Email: |
| dcole@uidaho.edu |
| Lab/Office Location: |
| Gibb Hall, Room 136 |
| Lab Phone: |
| (208) 885-2653 |
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| Research Interests: |
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| Intraflagellar Transport: |
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First identified in the green algae, Chlamydomonas, Intraflagellar Transport (IFT) involves the movement of large protein
complexes known as "rafts" along the length of all eukaryotic cilia and flagella. Rafts are moved out toward the distal
end of the organelle by kinesin-II (up to 2 um/sec) and moved back toward the cell body by cytoplasmic dynein 1b (up to 4 um/sec).
In Chlamydomonas, IFT rafts are composed of at least 18 polypeptides ranging from 20 to ~200 kDa and can be isolated as two
separate protein complexes known as Complex A and Complex B. Although we know that IFT is required for ciliary and flagellar
assembly, we have very little information on the mechanism underlying IFT function.
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| IFT may transport axonemal precursors: |
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Because IFT is required for ciliary/flagellar assembly, a popular model has developed in the field in which IFT functions to carry
axonemal precursors. This is an attractive model because assembly of cilia and flagella occurs out at the tip of the organelle. As
the structure becomes longer, the distance from cell body to the site of assembly (the distal tip) becomes greater. Thus, the cell
is faced with the transport problem of how to get the building supplies out to the construction site. IFT provides a practical means
to move axonemal precursors out to the distal tip of the flagellum. There are also other potential functions for IFT. For example,
IFT could be involved with the placement or removal of transmembrane proteins.
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| IFT polypeptides: |
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In order to better understand how IFT functions, we have focused on characterization of the rafts and their polypeptide subunits.
And, although these studies were initiated in green algae, all of the raft proteins are conserved in ciliated eukaryotes, including
man. For example, Chlamydomonas IFT88 is homologous to mouse Tg737, a protein that is associated with autosomal recessive
polycystic kidney disease (ARPKD). Subsequent analysis of mice carrying a mutation in Tg737, revealed that the primary cilia of the
renal collecting duct were poorly formed thus linking polycystic kidney disease to the primary cilia of the collecting duct.
Further analysis of these mutant mice has revealed that all cilia and flagella throughout its body are aberrant, providing further
evidence that IFT is essential in the assembly of ciliary organelles regardless of tissue or cell type.
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| IFT raft architecture: |
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One fundamental problem to solve is to determine how the raft polypeptides interact to assemble the raft structures. To do this, we
have developed an approach that combines chemical cross-linking of raft polypeptides followed by immunoprecipitation and MALDI-TOF
mass spectrometric analysis of cross-linked proteins. This allows us to identify neighboring proteins within the complex. To
complement this approach, we are also testing directly for protein-protein interaction by using the yeast two-hybrid system. The
combination of these techniques allows us to map out the architecture of the rafts. Other obvious problems to solve include
identifying how the motors dock to the rafts and how potential cargoes dock to the rafts.
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| Kinesin-II, the anterograde IFT motor: |
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Another area of research in our laboratory focuses on kinesin-II, the anterograde IFT motor. Kinesin-II is typically isolated as a
heterotrimeric complex consisting of 2 unique, albeit related, motor subunits and a third, nonmotor subunit usually referred to as
KAP (kinesin associated protein). First characterized in the sea urchin and mouse, kinesin-II is a multi-functional protein that is
not necessarily restricted to flagellar duties. One of the Chlamydomonas kinesin-II motor subunits, FLA10, was cloned in the
early 90's and analysis of a temperature-sensitive mutation (fla10) revealed that kinesin-II was essential for IFT. We have
recently cloned the other two Chlamydomonas kinesin-II subunits known as FLA10H (FLA10 homologue) and KAP. Sequence analysis
reveals that FLA10 is most homologous to the KIF3A subfamily while FLA10H is most homologous to the KIF3B subfamily. Analysis is
underway to determine how this kinesin docks to the rafts.
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| Selected Publications: |
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Cole, DG 2005 Intraflagellar transport: keeping the motors coordinated.
Curr. Biol. 15:R798-801.
Miller MS, Esparza JM, Lippa AM, Lux III FG, Cole DG, Dutcher SK 2005 Mutant
kinesin-2 motor subunits increase chromosome loss. Mol. Biol. Cell
16:3810-3820.
Lucker BF, Behal RH, Qin H, Siron LC, Taggart WD, Rosenbaum JL, Cole DG
(2005) Characterization of the intraflagellar transport complex B core: Direct
interaction of the IFT81 and IFT74/72 subunits. J. Biol. Chem.
280:27688-27696.
Pedersen LB, Miller MS, Geimer S, Leitch JM, Rosenbaum JL, Cole DG 2005
Chlamydomonas IFT172 is encoded by FLA11, interacts with CrEB1, and
regulates IFT at the flagellar tip. Curr Biol. 15:262-266.
Mueller J, Perrone CA, Bower R, Cole DG, Porter ME 2005 The FLA3 KAP
subunit is required for localization of Kinesin-2 to the site of flagellar
assembly and processive anterograde intraflagellar transport. Molec Biol
Cell 16:1341-1354.
Qin H, DR Diener, S Geimer, DG Cole, and JL Rosenbaum. 2004 Intraflagellar
transport (IFT) cargo: IFT transports flagellar precursors to the tip and
turnover products to the cell body. J Cell Biol.
164:255-266.
Cole DG, and MV Reedy. 2003 Algal morphogenesis: how Volvox turns itself
inside-out. Curr Biol. 13:R770-772.
Cole, D.G. 2003 The intraflagellar transport machinery of Chlamydomonas
reinhardtii. Traffic 4:435-442.
Pazour, GJ, SA Baker, JA Deane, DG Cole, BL Dickert, JL Rosenbaum, GB
Witman, and JC Besharse. 2002. The intraflagellar transport protein, IFT88, is
essential for vertebrate photoreceptor assembly and maintenance. J. Cell
Biol., 157:103-114.
Deane, JA, DG Cole, ES Seeley, DR Diener, and JL Rosenbaum. 2001.
Localization of intraflagellar transport protein IFT52 identifies basal body
transitional fibers as the docking site for IFT particles. Current Biol.
11:1586-1590.
Pazour GJ, BL Dickert, Y Vucica, ES Seeley, JL Rosenbaum, GB Witman, and DG
Cole. 2000. Chlamydomonas IFT88 and its mouse homologue,
polycystic kidney disease gene tg737, are required for assembly of cilia and
flagella. J. Cell Biol. 151:709-718.
Cole, DG. 1999. Kinesin-II, the heteromeric kinesin. Cell Mol. Life Sci. 56:217-226.
Rosenbaum, JL, DG Cole, and DR Diener. 1999. Intraflagellar transport: the
eyes have it. J. Cell Biol. 144:385-388.
Cole, DG, DR Diener, AL Himelblau, PL Beech, JC Fuster, and JL Rosenbaum.
1998. Chlamydomonas kinesin-II-dependent intraflagellar transport
(IFT): IFT particles contain proteins required for ciliary assembly in
Caenorhabditis elegans sensory neurons. J. Cell Biol.
141:993-1008.
Henson, JH, DG Cole, CD Roessner, S Capuano, RJ Mendola, and JM Scholey.
1997. The Heterotrimeric Motor Protein Kinesin-II Localizes to the Midpiece
and Flagellum of Sea Urchin and Sand Dollar Sperm. Cell Motil.
Cytoskel. 38: 29-37.
Cole, DG, WM Saxton, KB Sheehan, and JM Scholey. 1994. A 'Slow'
Homotetrameric Kinesin-Related Motor Protein Purified from
Drosophila Embryos. J. Biol. Chem. 269:
22913-22916.
Hall, K, DG Cole, Y Yeh, JM Scholey, and RJ Baskin. 1993. Force-Velocity
Relationships in Kinesin-Driven Motility. Nature 364:
457-459.
Cole, DG, SW Chinn, KP Wedaman, K Hall, T Vuong, and JM Scholey. 1993. A
Novel Heterotrimeric Kinesin Purified From Sea Urchin Eggs. Nature
366: 268-270.
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