Lateral Diffusion Anisotropy and Membrane Lipid/Skeleton Interaction in Outer Hair Cells

Monvel, Jacques Boutet de; Brownell, William E.; Ulfendahl, Mats

doi:10.1529/biophysj.105.076331

Cited by 38 publications

(23 citation statements)

References 67 publications

(100 reference statements)

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“…Our FRAP protocol for measuring di-8-ANEPPS lateral mobility in the OHC produced D values that were comparable to those reported in other studies of di-8-ANEPPS diffusion in OHCs (Oghalai et al 1999(Oghalai et al , 2000de Monvel et al 2006;Chen and Zhao 2007). Although our effective diffusion coefficients were somewhat larger, we attribute this to differences in experimental setup, diffusion models, and fitting routines, since our reported D values for di-8-ANEPPS diffusion in HEKs and OHCs were similar.…”

Section: Discussionsupporting

confidence: 86%

“…Previous work has measured lateral diffusion in OHCs using FRAP and demonstrated that the fluidity of the OHC plasma membrane is similar to other eukaryotic cells (Oghalai et al 1999(Oghalai et al , 2000de Monvel et al 2006). Interestingly, lipid lateral mobility in OHCs has been reported to be both voltage-and tension-dependent (Oghalai et al 2000).…”

Section: Introductionmentioning

confidence: 84%

“…The structure of di-8-ANEPPS is analogous to lipids, with a polar head region and a nonpolar tail region. This suggests that di-8-ANEPPS lateral mobility is similar to that of native constituent lipids, and di-8-ANEPPS cleanly and homogeneously labels the plasma membranes of both OHCs and HEKs (Oghalai et al 1998(Oghalai et al , 1999(Oghalai et al , 2000de Monvel et al 2006;Chen and Zhao 2007;Greeson and Raphael 2007). While the use of DMSO as a carrier for di-8-ANEPPS may have some effect on the material properties of the OHC plasma membrane, all cells were treated identically with di-8-ANEPPS, and we do not believe that this treatment in any way predisposed OHCs to be abnormally sensitive to cholesterol manipulations.…”

Section: Ohc Isolation and Fluorescent Labelingmentioning

confidence: 96%

“…Interestingly, lipid lateral mobility in OHCs has been reported to be both voltage-and tension-dependent (Oghalai et al 2000). Additionally, lipid diffusion in the OHC has been reported to be anisotropic, faster in the axial than circumferential direction (de Monvel et al 2006). This observation is attributed to the structure and orientation of the cortical actin-spectrin cytoskeleton (de Monvel et al 2006) and/or the small, structural domains observed in the OHC plasma membrane (Zhang and Kalinec 2002).…”

Section: Introductionmentioning

confidence: 99%

“…Additionally, lipid diffusion in the OHC has been reported to be anisotropic, faster in the axial than circumferential direction (de Monvel et al 2006). This observation is attributed to the structure and orientation of the cortical actin-spectrin cytoskeleton (de Monvel et al 2006) and/or the small, structural domains observed in the OHC plasma membrane (Zhang and Kalinec 2002). Recent work has also shown that intense noise exposure decreases lateral diffusion in the OHC plasma membrane, suggesting that alterations in membrane material properties are involved in the mechanism of noise damage (Chen and Zhao 2007).…”

Section: Introductionmentioning

confidence: 99%

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Lipid Lateral Mobility in Cochlear Outer Hair Cells: Regional Differences and Regulation by Cholesterol

Organ

Raphael

2009

JARO

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The outer hair cell (OHC) lateral plasma membrane houses the transmembrane protein prestin, a necessary component of the yet unknown molecular mechanism (s) underlying electromotility and the exquisite sensitivity and frequency selectivity of mammalian hearing. The importance of the plasma membrane environment in modulating OHC electromotility has been substantiated by recent studies demonstrating that membrane cholesterol alters prestin activity in a manner consistent with cholesterol-induced changes in auditory function. Cholesterol is known to affect membrane material properties, and measurements of lipid lateral mobility provide a method to asses these changes in living OHCs. Using fluorescence recovery after photobleaching (FRAP), we characterized regional differences in the lateral diffusion of the lipid analog di-8-ANEPPS in OHCs and investigated whether lipid mobility, which reflects membrane fluidity, is sensitive to membrane cholesterol. FRAP experiments revealed quantitative differences in lipid lateral mobility among the apical, lateral, and basal regions of the OHC and demonstrated that diffusion in individual regions is uniquely sensitive to cholesterol manipulations. Interestingly, in the lateral region, both cholesterol depletion and loading significantly reduced the effective diffusion coefficient from control values. Thus, the fluidity of the OHC lateral plasma membrane is regulated by cholesterol levels in a non-monotonic manner, suggesting that the overall material properties of the lateral plasma membrane are optimally tuned for OHC function in the native state. These results support the idea that the cholesteroldependent regulation of prestin function and electromotility correlates with changes in the properties of the lipid environment that surrounds and supports prestin.

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Section: Discussionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 84%

Section: Ohc Isolation and Fluorescent Labelingmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Lipid Lateral Mobility in Cochlear Outer Hair Cells: Regional Differences and Regulation by Cholesterol

Organ

Raphael

2009

JARO

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Endogenous ABA concentration and cytoplasmic membrane fluidity in microspores of oilseed rape (Brassica napus L.) genotypes differing in responsiveness to androgenesis induction

et al. 2013

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Key messageA better understanding of androgenesis with a focus on the changes in plasma membrane fluidity and endogenous ABA content affecting embryogenesis induction in microspore suspension ofB. napus.AbstractChanges in plasma membrane fluidity (MF) and ABA content associated with androgenesis induction were under the study. Both parameters were monitored in microspores of two Brassica napus L. genotypes differing in their response to androgenic induction under heat (1 day at 32 °C). MF was assessed by DPH method. ABA content was evaluated by ELISA. Heat caused microspores’ plasma membrane to become more rigid. Lower MF in microspores of ‘DH 4079’ (of high androgenic potential) seems to maintain proper cell protection and leads to efficient embryogenesis induction. Plasma membrane remodelling coincided with changes of ABA content in microspores and in the culture medium in both genotypes. ABA concentration (μM) and ABA content (fmol per 104 microspores or pmol g−1 FW) were for the first time measured in microspores. ABA concentration (μM) in microspores and in the culture medium (nM) differed significantly for the genotype and the treatment. The interaction between both variables was also significant. In general, ABA content ranged from <3.5 to 87.1 fmol per 104 microspores. The highest content of ABA was detected in ‘DH 4079’ microspores at 32 °C. Assuming a mean microspores’ radius of 10 μm, it corresponds to ABA concentration of 2.1 μM. Heat shock resulted in quantum of medium pH reduction (0.1–0.2) and increased levels of ABA in microspores and in the medium of both tested genotypes. However, heat induced increase of ABA content in microspores of non-responsive ‘Campino’ had no clear-cut impact, on androgenesis induction efficiency, which suggests a more complex mechanism of process initiation.

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Immune atomic force microscopy of prestin-transfected CHO cells using quantum dots

Murakoshi

Iida

Kumano

et al. 2008

Pflugers Arch - Eur J Physiol

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Prestin, a membrane protein of the outer hair cells (OHCs), is known to be the motor which drives OHC somatic electromotility. Electron microscopic studies showed the lateral membrane of the OHCs to be densely covered with 10-nm particles, they being believed to be a motor protein. Imaging by atomic force microscopy (AFM) of prestin-transfected Chinese hamster ovary (CHO) cells revealed 8- to 12-nm particle-like structures to possibly be prestin. However, since there are many kinds of intrinsic membrane proteins other than prestin in the plasma membranes of OHCs and CHO cells, it was impossible to clarify which structures observed in such membranes were prestin. In the present study, an experimental approach combining AFM with quantum dots (Qdots), used as topographic surface markers, was carried out to detect individual prestin molecules. The inside-out plasma membranes were isolated from the prestin-transfected and untransfected CHO cells. Such membranes were then incubated with antiprestin primary antibodies and Qdot-conjugated secondary antibodies. Fluorescence labeling of the prestin-transfected CHO cells but not of the untransfected CHO cells was confirmed. The membranes were subsequently scanned by AFM, and Qdots were clearly seen in the prestin-transfected CHO cells. Ring-like structures, each with four peaks and one valley at its center, were observed in the vicinity of the Qdots, suggesting that these structures are prestin expressed in the plasma membranes of the prestin-transfected CHO cells.

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Lateral Diffusion Anisotropy and Membrane Lipid/Skeleton Interaction in Outer Hair Cells

Cited by 38 publications

References 67 publications

Lipid Lateral Mobility in Cochlear Outer Hair Cells: Regional Differences and Regulation by Cholesterol

Lipid Lateral Mobility in Cochlear Outer Hair Cells: Regional Differences and Regulation by Cholesterol

Endogenous ABA concentration and cytoplasmic membrane fluidity in microspores of oilseed rape (Brassica napus L.) genotypes differing in responsiveness to androgenesis induction

Immune atomic force microscopy of prestin-transfected CHO cells using quantum dots

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