scholarly journals Essential role of non-vesicular lipid transport in microtubule-controlled cell polarisation

2020 ◽  
Author(s):  
M. Hersberger-Trost ◽  
D. Dreher ◽  
S.M. Huisman ◽  
A.R. Kijowski ◽  
M. Gemünden ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Molecular Basis ◽  
De Novo ◽  
Lipid Transport ◽  
Membrane Domains ◽  
Fundamental Biological Process ◽  
Dependent Cell ◽  
Plasma Membrane Domains ◽  
Dependent Pathway

AbstractCell polarisation is a fundamental biological process. Fission yeast is a key model system to study the molecular basis of microtubule-controlled cell polarisation. In this process, cells define prospective growth sites by generating distinct plasma membrane domains enriched in de novo synthesised sterols. Microtubules restrict the number and location of these domains by depositing factors at the cell poles. The mechanisms underlying such sterol-rich membrane domain formation and polarisation are largely unknown. We found that the oxysterol-binding proteins kes1p, osh2p and kes3p define three independent sterol delivery pathways to the plasma membrane. These mediate different phases of cell polarisation in a phosphoinositide-dependent fashion and differ in their requirement for vesicular trafficking steps. The redundant, kes1p- and osh2p-dependent pathways are vital and prime cell polarisation by mediating the formation of randomly distributed sterol-rich plasma membrane domains. Subsequent microtubule-controlled polarisation of these domains preferentially employs kes1p that directly delivers sterols to the plasma membrane independent of cdc42p. In cells lacking kes1p, polarisation becomes cdc42p-dependent, utilising mainly the kes3p-dependent pathway. Our study uncovers an essential biological function for non-vesicular lipid transport and establishes a molecular basis for different sterol-delivery pathways acting in cdc42p-independent and cdc42p-dependent cell polarisation.

scholarly journals Rapid Nonvesicular Transport of Sterol between the Plasma Membrane Domains of Polarized Hepatic Cells

2002 ◽  
Vol 277 (33) ◽  
pp. 30325-30336
Author(s):  
Daniel Wüstner ◽  
Andreas Herrmann ◽  
Mingming Hao ◽  
Frederick R. Maxfield
Keyword(s):  
Plasma Membrane ◽  
Membrane Domains ◽  
Hepatic Cells ◽  
Plasma Membrane Domains

scholarly journals Synergistic Assembly of Linker for Activation of T Cells Signaling Protein Complexes in T Cell Plasma Membrane Domains

2003 ◽  
Vol 278 (22) ◽  
pp. 20389-20394 ◽  
Author(s):  
Lorian C. Hartgroves ◽  
Joseph Lin ◽  
Hanno Langen ◽  
Tobias Zech ◽  
Arthur Weiss ◽  
...  
Keyword(s):  
T Cells ◽  
Plasma Membrane ◽  
T Cell ◽  
Protein Complexes ◽  
Membrane Domains ◽  
Cell Plasma Membrane ◽  
Signaling Protein ◽  
Cell Plasma ◽  
Plasma Membrane Domains

Stimulation of calcium influx by platelet activating factor in Dictyostelium

1995 ◽  
Vol 108 (4) ◽  
pp. 1597-1603
Author(s):  
R. Schaloske ◽  
C. Sordano ◽  
S. Bozzaro ◽  
D. Malchow
Keyword(s):  
Plasma Membrane ◽  
G Protein ◽  
Dictyostelium Discoideum ◽  
Calcium Influx ◽  
Platelet Activating Factor ◽  
Inactive Compound ◽  
Time Period ◽  
Dependent Pathway ◽  
Stimulation Of

Platelet activating factor (PAF) induces Ca2+ influx in Dictyostelium discoideum. In this investigation we used this activity to analyze the mechanism of PAF action. We found that PAF activity was confined to the period of spike-shaped oscillations and suggest that the role of PAF is to augment cAMP relay. PAF seems to act only a few times during this time period of two hours, since Ca2+ entry adapted to a subsequent stimulus for about 30 minutes. PAF showed a reduced response in the G protein beta- strain LW14 and was unable to induce Ca2+ influx in the G alpha 2- strains HC85 and JM1. The latter expresses the cAMP receptors cAR1 constitutively, and exhibits cAMP-induced Ca2+ influx, albeit at a reduced level. In order to decide whether the inability of PAF to elicit a Ca2+ response in JM1 cells was due to the lack of differentiation and/or the lack of G alpha 2, we inhibited the IP3-dependent pathway with compound U73122 and found that Ca2+ entry was blocked, whereas a closely related inactive compound, U73343, did not alter the response. In agreement with this, NBD-Cl, an inhibitor of Ca2+ uptake into the IP3-sensitive store in Dictyostelium, also abolished PAF activity. The latter was not inhibited by the plasma membrane antagonists BN-52021 or WEB 2170. Therefore PAF seems to operate intracellularly via the IP3-signalling pathway at or upstream of the IP3-sensitive store.

The GTPase Rac1 selectively regulates Salmonella invasion at the apical plasma membrane of polarized epithelial cells

2001 ◽  
Vol 114 (7) ◽  
pp. 1331-1341 ◽  
Author(s):  
A.K. Criss ◽  
D.M. Ahlgren ◽  
T.S. Jou ◽  
B.A. McCormick ◽  
J.E. Casanova
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cells ◽  
Mdck Cells ◽  
Bacterial Pathogen ◽  
Small Gtpases ◽  
Apical Plasma Membrane ◽  
Membrane Domains ◽  
Intestinal Epithelial ◽  
Actin Structure

The bacterial pathogen Salmonella typhimurium colonizes its animal hosts by inducing its internalization into intestinal epithelial cells. This process requires reorganization of the actin cytoskeleton of the apical plasma membrane into elaborate membrane ruffles that engulf the bacteria. Members of the Ρ family of small GTPases are critical regulators of actin structure, and in nonpolarized cells, the GTPase Cdc42 has been shown to modulate Salmonella entry. Because the actin architecture of epithelial cells is organized differently from that of nonpolarized cells, we examined the role of two ‘Rgr; family GTPases, Cdc42 and Rac1, in invasion of polarized monolayers of MDCK cells by S. typhimurium. Surprisingly, we found that endogenous Rac1, but not Cdc42, was activated during bacterial entry at the apical pole, and that this activation required the bacterial effector protein SopE. Furthermore, expression of dominant inhibitory Rac1 but not Cdc42 significantly inhibited apical internalization of Salmonella, indicating that Rac1 activation is integral to the bacterial entry process. In contrast, during basolateral internalization, both Cdc42 and Rac1 were activated; however, neither GTPase was required for entry. These findings, which differ significantly from previous observations in nonpolarized cells, indicate that the host cell signaling pathways activated by bacterial pathogens may vary with cell type, and in epithelial tissues may further differ between plasma membrane domains.

Sign in / Sign up

Export Citation Format

Share Document