Sukla Roychowdhury

Sukla Roychowdhury
University of Texas at El Paso | UTEP · Department of Biological Sciences

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39
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Publications

Publications (39)
Article
Full-text available
The βγ subunit of heterotrimeric G proteins, a key molecule in the G protein-coupled receptors (GPCRs) signaling pathway, has been shown to be an important factor in the modulation of the microtubule cytoskeleton. Gβγ has been shown to bind to tubulin, stimulate microtubule assembly, and promote neurite outgrowth of PC12 cells. In this study, we de...
Article
Microtubules (MTs) constitute a crucial part of the cytoskeleton and are essential for cell division and differentiation, cell motility, intracellular transport, and cell morphology. Precise regulation of MT assembly and dynamics is essential for the performance of these functions. Although much progress has been made in identifying and characteriz...
Article
Full-text available
Background: The migration of tumor cells is critical in spreading cancers through the lymphatic nodes and circulatory systems. Although arachidonic acid (AA) and its soluble metabolites have been shown to induce the migration of breast and colon cancer cells, the mechanism by which it induces such migration has not been fully understood. Objectiv...
Chapter
Full-text available
Microtubules (MTs), a major component of cell cytoskeleton, exhibit diverse cellular functions including cell motility, intracellular transport, cell division, and differentiation. These functions of MTs are critically dependent on their ability to polymerize and depo-lymerize. Although a significant progress has been made in identifying cellular f...
Article
Full-text available
Although encystation (or cyst formation) is an important step of the life cycle of Giardia, the cellular events that trigger encystation is poorly understood. Because membrane microdomains are involved in inducing growth and differentiation in many eukaryotes, we wondered if these raft-like domains are assembled by this parasite and participate in...
Article
Full-text available
BACKGROUND: Assembly and disassembly of microtubules (MTs) is critical for neurite outgrowth and differentiation. Evidence suggests that nerve growth factor (NGF) induces neurite outgrowth from PC12 cells by activating the receptor tyrosine kinase, TrkA. G protein-coupled receptors (GPCRs) as well as heterotrimeric G proteins are also involved in r...
Article
Full-text available
The production of viable cysts by Giardia is essential for its survival in the environment and for spreading the infection via contaminated food and water. The hallmark of cyst production (also known as encystation) is the biogenesis of encystation-specific vesicles (ESVs) that transport cyst wall proteins to the plasma membrane of the trophozoite...
Conference Paper
Assembly and disassembly of microtubules (MTs) is critical for axon and dendrites formation, and for neurite outgrowth. During neuronal degeneration, the architecture of MTs and proteins associated with them are severely altered. We have shown earlier that the βγ (beta-gamma) subunit of G proteins binds to tubulin stimulating MT assembly. More rece...
Conference Paper
Full-text available
s: Thirty-Fourth Annual CTRC‐AACR San Antonio Breast Cancer Symposium‐‐ Dec 6‐10, 2011; San Antonio, TX Background: In invasive breast cancers, cancerous cells spread outside the ducts of the breast and metastasize to lung and other tissues. Although the rapid arachidonic acid (AA) metabolism and concomitant increase of eicosanoid molecules are in...
Conference Paper
Neurite outgrowth and differentiation is a complex and finely regulated process that requires tight coordination between assembly/disassembly of microtubules and actin filaments. However, the precise molecular mechanisms that drive these cytoskeletal changes during neurite outgrowth are poorly understood. Heterotrimeric G proteins are important for...
Article
Full-text available
Giardia lamblia, a protozoan parasite, infects a wide variety of vertebrates, including humans. Studies indicate that this anaerobic protist possesses a limited ability to synthesize lipid molecules de novo and depends on supplies from its environment for growth and differentiation. It has been suggested that most lipids and fatty acids are taken u...
Article
The early-divergent protozoan Giardia lamblia, which is a major cause of waterborne enteric disease worldwide, was shown to possess limited lipid synthesis ability and to depend upon preformed lipid molecules for energy production and membrane biosynthesis. Therefore, questions regarding how Giardia imports and utilizes exogenous lipids are importa...
Chapter
Giardia and Cryptosporidium are both parasites of considerable global interest due to the gastrointestinal problems the organisms can cause in humans as well as domestic and wild animals. This book presents an overview of recent research. The chapters discuss topics from taxonomy; nomenclature and evolution to molecular epidemiology; advances in di...
Conference Paper
Neurite outgrowth is a complex and finely regulated process that requires tight coordination between assembly/disassembly of microtubules and actin filaments and is regulated by G-protein coupled receptors in neurons. We have shown earlier that βγ subunits of G proteins are involved in promoting microtubule assembly in cultured NIH3T3 and PC12 cell...
Article
Heterotrimeric Gproteins participate in signal transduction by transferring signals from cell surface receptors to intracellular effector molecules. Gproteins also interact with microtubules and participate in microtubule-dependent centrosome/chromosome movement during cell division, as well as neuronal differentiation. In recent years, significant...
Article
Full-text available
Although encystation (cyst formation) is important for the survival of Giardia lamblia outside its human host, the molecular events that prompt encystation have not been fully elucidated. Here, we demonstrate that sphingolipids (SLs), which are important for the growth and differentiation of many eukaryotes, play key roles in giardial encystation....
Article
The βγ subunit of G proteins (Gβγ) is known to transfer signals from cell surface receptors to intracellular effector molecules. Recent results suggest that Gβγ also interacts with microtubules and is involved in the regulation of the mitotic spindle. In the current study, the anti-microtubular drug nocodazole was employed to investigate the mechan...
Article
Full-text available
Although identified as an early-diverged protozoan, Giardia lamblia shares many similarities with higher eukaryotic cells, including an internal membrane system and cytoskeleton, as well as secretory pathways. However, unlike many other eukaryotes, Giardia does not synthesize lipids de novo, but rather depends on exogenous sources for both energy p...
Article
Heterotrimeric G proteins participate in signal transduction by transferring signals from cell surface receptors to intracellular effector molecules. Interestingly, recent results suggest that G proteins also interact with microtubules and participate in cell division and differentiation. It has been shown earlier that both alpha and betagamma subu...
Article
Full-text available
G proteins serve many functions involving the transfer of signals from cell surface receptors to intracellular effector molecules. Considerable evidence suggests that there is an interaction between G proteins and the cytoskeleton. In this report, G protein alpha subunits Gi1alpha, Gsalpha, and Goalpha are shown to activate the GTPase activity of t...
Article
alpha and betagamma subunits of G proteins are thought to transduce signals from cell surface receptors to intracellular effector molecules. Galpha and Gbetagamma have also been implicated in cell growth and differentiation, perhaps due to their association with cytoskeletal components. In this report Gbetagamma is shown to modulate the cytoskeleto...
Article
Full-text available
α and βγ subunits of G proteins are thought to transduce signals from cell surface receptors to intracellular effector molecules. Gα and Gβγ have also been implicated in cell growth and differentiation, perhaps due to their association with cytoskeletal components. In this report Gβγ is shown to modulate the cytoskeleton by regulation of microtubul...
Article
It has been suggested that dimeric tubulin can participate in the signal transduction process through its association with the GTP-binding (G) proteins Gs and Gi1. Using the photoaffinity GTP analog, azidoanilido-GTP, it has been shown that the transfer of nucleotide from tubulin to G alpha s and G alpha i1 is the key step of this activation. The b...
Article
Cytoskeletal proteins have been demonstrated to interact with elements which mediate neuronal signal transduction. This laboratory has shown that tubulin forms complexes with certain G proteins and transfers GTP to them, and such nucleotide transfer correlates well with the inhibition of adenylyl cyclase. A previous study showed that tubulin-G prot...
Article
Ethacrynic acid (ECA) is a sulfhydryl reactive diuretic drug. Recent studies show that ocular administration of ECA may have potential efficacy for treatment of glaucoma. ECA affects cell shape in cultured cells from the eye outflow pathway and the microtubule system is disrupted. We have studied the effect of ECA on microtubule protein (MTP) (tubu...
Article
The active site of the exchangeable nucleotide-binding site of tubulin was studied by using diastereoisomers A (Sp) and B (Rp) of guanosine 5'-O-(2-thiotriphosphate) (GTP beta S) where the phosphorus atom to which sulfur is attached is chiral. Turbidimetric measurements were used to follow kinetics, and electron microscopy was used to evaluate poly...
Article
Two conflicting interpretations on the role of guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) in microtubule protein and tubulin assembly have been previously reported. One study finds that GTP gamma S promotes assembly while another study reports that GTP gamma S is a potent inhibitor of microtubule assembly. We have examined the potential role...
Article
Fast-performance liquid chromatography was used to purify assembly-competent tubulin from porcine brain microtubule protein prepared by two cycles of assembly-disassembly. Microtubule protein (1-100 mg at 1.5-2.5 mg/ml) in buffer consisting of 0.1 M 2-(N-morpholino)ethanesulfonic acid, 0.5 mM MgCl2, 1 mM EGTA, 0.3 M KCl, and 0.02 mM GTP (pH 6.6) wa...
Article
Poly(L-lysine) was found to enhance colchicine binding activity of brain tubulin to a several folds. Bases of biological interests that were tested and found to be inactive were spermine, spermidine and even L-lysine. Part of this enhance binding is due to the increase in the affinity of colchicine-tubulin interaction in the presence of poly(L-lysi...
Article
In vitro polymerization of purified goat brain tubulin is stimulated at low Ni2+ concentration, whereas at high nickel concentration (greater than 1 . 10(-4)) polymerization is inhibited. Ni2+, over the concentration range of 1 . 10(-4)-1 . 10(-3) M, enhances the rate of colchicine binding to tubulin, although in its presence the colchicine binding...
Article
Unlike normal microtubule assembly, the assembly of DEAE-purified goat brain tubulin in presence of Zn(II) is not inhibited by suprastoichiometric concentrations of antimicrotubular drugs like colchicine and podophyllotoxin. However, assembly in the presence of Zn(II) is inhibited by vinblastine. Vinblastine sensitivity of the assembly process depe...

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