Title
A dynein light intermediate chain, D1bLIC, is required for retrograde intraflagellar transport
GSBS Program
Biochemistry & Molecular Pharmacology
UMMS Affiliation
Graduate School of Biomedical Sciences; Department of Cell Biology; Program in Molecular Medicine
Date
7-23-2004
Document Type
Article
Medical Subject Headings
Amino Acid Sequence; Animals; Base Sequence; Biological Transport; Chlamydomonas reinhardtii; Dynein ATPase; Flagella; Humans; Molecular Motor Proteins; Molecular Sequence Data; Mutagenesis, Site-Directed; Phenotype; Phylogeny; Protein Conformation; Protein Subunits; Protozoan Proteins
Disciplines
Life Sciences | Medicine and Health Sciences
Abstract
Intraflagellar transport (IFT), the bidirectional movement of particles along flagella, is essential for flagellar assembly. The motor for retrograde IFT in Chlamydomonas is cytoplasmic dynein 1b, which contains the dynein heavy chain DHC1b and the light intermediate chain (LIC) D1bLIC. To investigate a possible role for the LIC in IFT, we identified a d1blic mutant. DHC1b is reduced in the mutant, indicating that D1bLIC is important for stabilizing dynein 1b. The mutant has variable length flagella that accumulate IFT-particle proteins, indicative of a defect in retrograde IFT. Interestingly, the remaining DHC1b is normally distributed in the mutant flagella, strongly suggesting that the defect is in binding of cargo to the retrograde motor rather than in motor activity per se. Cell growth and Golgi apparatus localization and morphology are normal in the mutant, indicating that D1bLIC is involved mainly in retrograde IFT. Like mammalian LICs, D1bLIC has a phosphate-binding domain (P-loop) at its N-terminus. To investigate the function of this conserved domain, d1blic mutant cells were transformed with constructs designed to express D1bLIC proteins with mutated P-loops. The constructs rescued the mutant cells to a wild-type phenotype, indicating that the function of D1bLIC in IFT is independent of its P-loop.
Rights and Permissions
Citation: Mol Biol Cell. 2004 Oct;15(10):4382-94. Epub 2004 Jul 21. Link to article on publisher's site