The role of the microtubule-based motor, kinesin, in membrane trafficking has been investigated in resting and stimulated acinar cells from rabbit lacrimal gland, a cholinergically controlled secretory tissue. Microtubule-dependent motors from extracts of control and carbachol-treated acini were isolated by microtubule-affinity purification and their activity was determined using a video-enhanced differential interference contrast microscopy assay for microtubule gliding. The observation that carbachol treatment resulted in a 2.2-fold stimulation of the frequency of GTP-dependent microtubule gliding in fractions isolated by microtubule-affinity purification and GTP release suggested that kinesin was a target of carbachol-induced stimulation. Resolution of membranes from resting cells by fractionation on a sorbitol density gradient followed by partitioning analysis in a dextran-polyethyleneglycol two-phase system revealed that membrane-associated kinesin codistributed with Golgi-derived membranes, a post-Golgi secretory compartment designated Hex1, membranes from a trans Golgi network-like compartment, endoplasmic reticulum and a group of putative lysosomal membranes containing cathepsin B. Comparable fractionation of carbachol-treated acini showed that stimulation caused redistributions of membrane-associated kinesin, the secretory enzyme beta-hexosaminidase, and galactosyltransferase that appeared to reflect both a reorganization within the Golgi complex and a return of material to the Golgi complex from the secretory pathway. Our findings that carbachol promotes activation of lacrimal acinar kinesin as well as major shifts in kinesin-membrane association within the secretory pathway suggests that kinesin plays a major role in secretory vesicle assembly, apical secretion, and/or secretory vesicle membrane recycling in the lacrimal gland.
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http://dx.doi.org/10.1006/exer.1996.0198 | DOI Listing |
Open Biol
October 2024
Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada K1H 8M5.
Curr Biol
October 2024
Department of Cell and Chemical Biology, ONCODE institute, Leiden University Medical Center LUMC, Einthovenweg 20, 2333 ZC Leiden, the Netherlands. Electronic address:
Kinesin and dynein-dynactin motors move endosomes and other vesicles bidirectionally along microtubules, a process mainly studied under in vitro conditions. Here, we provide a physiological bidirectional transport model following color-coded, endogenously tagged transport-related proteins as they move through a crowded cellular environment. Late endosomes (LEs) surf bidirectionally on Protrudin-enriched endoplasmic reticulum (ER) membrane contact sites, while hopping and gliding along microtubules and bypassing cellular obstacles, such as mitochondria.
View Article and Find Full Text PDFCells
September 2023
Institute for Biology and Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany.
The faithful formation and, consequently, function of a synapse requires continuous and tightly controlled delivery of synaptic material. At the presynapse, a variety of proteins with unequal molecular properties are indispensable to compose and control the molecular machinery concerting neurotransmitter release through synaptic vesicle fusion with the presynaptic membrane. As presynaptic proteins are produced mainly in the neuronal soma, they are obliged to traffic along microtubules through the axon to reach the consuming presynapse.
View Article and Find Full Text PDFJ Cell Biol
October 2022
Cellular Biology, University of Georgia, Athens, GA.
The GTPase Arl13b participates in ciliary protein transport, but its contribution to intraflagellar transport (IFT), the main motor-based protein shuttle of cilia, remains largely unknown. Chlamydomonas arl13 mutant cilia were characterized by both abnormal reduction and accumulation of select membrane-associated proteins. With respect to the latter, a similar set of proteins including phospholipase D (PLD) also accumulated in BBSome-deficient cilia.
View Article and Find Full Text PDFJ Cell Sci
June 2022
Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark.
The kinesin-3 motor KIF13B functions in endocytosis, vesicle transport and regulation of ciliary length and signaling. Direct binding of the membrane-associated guanylate kinase (MAGUK) DLG1 to the MAGUK-binding stalk domain of KIF13B relieves motor autoinhibition and promotes microtubule plus-end-directed cargo transport. Here, we characterize angiomotin (AMOT) isoform 2 (p80, referred to as Ap80) as a novel KIF13B interactor that promotes binding of another MAGUK, the polarity protein and Crumbs complex component PALS1, to KIF13B.
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