A5068160640- Cellular Mechanics and Interactions
- 3D Printing in Biomedical Research
- Protein Kinase Regulation and GTPase Signaling
- Microtubule and mitosis dynamics
- Cellular transport and secretion
- Phosphodiesterase function and regulation
- Advanced Fluorescence Microscopy Techniques
- Cell Adhesion Molecules Research
- Nitric Oxide and Endothelin Effects
- Cholinesterase and Neurodegenerative Diseases
- Neurobiology and Insect Physiology Research
- Receptor Mechanisms and Signaling
- Protist diversity and phylogeny
- Neuroscience and Neural Engineering
- Biocrusts and Microbial Ecology
- Enzyme function and inhibition
- Ion channel regulation and function
- Retinal Development and Disorders
- thermodynamics and calorimetric analyses
- Slime Mold and Myxomycetes Research
- Muscle Physiology and Disorders
- Planarian Biology and Electrostimulation
- Lipid Membrane Structure and Behavior
- Mathematical Biology Tumor Growth
- Force Microscopy Techniques and Applications
University of Groningen
2011-2024
University of British Columbia
2021
National Institutes of Health
2017
Molecular Research Institute
2008
Wageningen University & Research
2005
Boston Biomedical Research Institute
2002
College Board
1998
Johns Hopkins University
1991
Substance Abuse and Mental Health Services Administration
1991
Leiden University
1979-1990
Abstract Mutations in LRRK2 are a common cause of genetic Parkinson’s disease (PD). is multi-domain Roco protein, harbouring kinase and GTPase activity. In analogy with bacterial homologue, was proposed to act as activated by dimerization (GAD), while recent reports suggest exist under monomeric dimeric form vivo. It however unknown how oligomerization regulated. Here, we show that homologous protein depends on the nucleotide load. The mainly nucleotide-free GDP-bound states, it forms...
Eukaryotic cells extend pseudopodia for movement. In the absence of external cues, move in random directions, but with a strong element persistence that keeps them moving same direction Persistence allows to disperse over larger areas and is instrumental enter new environments where spatial cues can lead cell. Here we explore cell movement by analyzing direction, size timing approximately 2000 are extended Dictyostelium cells. The results show pseudpopod perpendicular surface curvature at...
The mechanism of eukaryotic chemotaxis remains unclear despite intensive study. most frequently described acts through attractants causing actin polymerization, in turn leading to pseudopod formation and cell movement. We recently proposed an alternative mechanism, supported by several lines data, which pseudopods are made a self-generated cycle. If chemoattractants present, they modulate the cycle rather than directly polymerization. aim this work is test explanatory predictive powers such...
Suspensions of 3':5'-cyclic AMP (cAMP)-sensitive cells Dictyostelium discoideum responded to a cAMP pulse with increased GMP (cGMP) levels. Under the assay conditions used (2 x 10(8) per ml in 10 mM phosphate buffer, pH 6.0) (5 10(-8) M final concentration) cGMP levels from 1 pmol 10(7) 7 sec and basal were recovered 20-25 sec. accumulation did not occur when cAMP-insensitive stage. cAMP-sensitive triggered by 5 5'-CH(2)-cAMP or 10(-5) adenosine-5'-methylmonophosphate (5'-AMPMe) but after...
Intracellular water concentrations in single living cells were visualized by nonlinear coherent anti-Stokes Raman scattering (CARS) microscopy. In combination with isotopic exchange measurements, CARS microscopy allowed the real-time observation of transient intracellular hydrodynamics at a high spatial resolution. Studies microorganism Dictyostelium discoideum indicated presence microscopic region near plasma membrane where mobility molecules is severely restricted. Modeling eventuated...
A series cAMP derivatives with modifications in the adenine, ribose and cyclophosphate moiety were screened for their binding affinity two types of cAMP‐binding sites mammalian protein kinase type I. In addition, activation by these analogs was monitored. The data indicate that is bound to both a comparable manner: adenine appears have no hydrogen‐bond interactions sites, whereas may be three hydrogen bonds involving 2′, 3′ 5′ positions cAMP. are not conclusive about nature interaction...
Chemotaxis is the ability of cells to move in direction an external gradient signaling molecules. Cells are guided by actin-filled protrusions front, whereas myosin filaments retract rear cell. Previous work demonstrated that chemotaxis unpolarized amoeboid Dictyostelium discoideum mediated two parallel pathways, phosphoinositide-3-kinase (PI3K) and phospholipase A2 (PLA2). Here, we show polarized exhibit very good with inhibited PI3K PLA2 activity. Using genetic screens, demonstrate this...
The mechanism of chemotaxis is one the most interesting issues in modern cell biology. Recent work shows that shallow chemoattractant gradients do not induce generation pseudopods, as has been predicted many models. This poses question how else cells can steer towards chemoattractants. Here we use a new computational algorithm to analyze extension pseudopods by Dictyostelium cells. We show gradient cAMP induces small bias direction pseudopod extension, without significantly affecting...
The analysis of the inositol cycle in Dictyostelium discoideum cells is complicated by limited uptake [3H]inositol (0.2% applied radioactivity 6 h), and conversion into water-soluble metabolites that are eluted near position 1,4,5-trisphosphate [Ins(1,4,5)P3] on anion-exchange h.p.l.c. columns. was improved to 2.5% electroporation presence [3H]inositol; optimal at two 210 microseconds pulses 7 kV. Cells remained viable responsive chemotactic signals after electroporation. intracellular...
Chemotaxis toward different cyclic adenosine monophosphate (cAMP) concentrations was tested in Dictyostelium discoideum cell lines with deletion of specific genes together drugs to inhibit one or all combinations the second-messenger systems PI3-kinase, phospholipase C (PLC), A2 (PLA2), and cytosolic Ca2+. The results show that inhibition either PI3-kinase PLA2 inhibits chemotaxis shallow cAMP gradients, whereas both enzymes must be inhibited prevent steep suggesting are two redundant...
Mutations in human leucine-rich-repeat kinase 2 (LRRK2) have been found to be the most frequent cause of late-onset Parkinson disease. Here we show that Dictyostelium discoideum Roco4 is a suitable model study structural and biochemical characteristics LRRK2 can used for optimization current identification new inhibitors. We solved structure wild-type, disease-related mutants G1179S L1180T (G2019S I2020T LRRK2) complex with inhibitor H1152. Taken together, our data give important insight...
Many eukaryotic cells regulate their mobility by external cues. Genetic studies have identified >100 components that participate in chemotaxis, which hinders the identification of conceptual framework how sense and respond to shallow chemical gradients. The activation Ras occurs during basal locomotion is an essential connector between receptor cytoskeleton chemotaxis. Using a sensitive assay for activated Ras, we show here F-actin forms two excitable systems are coupled through mutual...
Conventional myosin functions universally as a generator of motive force in eukaryotic cells. Analysis mutants the microorganism Dictyostelium discoideum revealed that also provides resistance against high external osmolarities. An osmo-induced increase intracellular guanosine 3′,5′-monophosphate was shown to mediate phosphorylation three threonine residues on tail, which caused relocalization required resist osmotic stress. This redistribution allowed cells adopt spherical shape and may...