Limits...
Membrane expansion increases endocytosis rate during mitosis.

Raucher D, Sheetz MP - J. Cell Biol. (1999)

Bottom Line: Mitosis in mammalian cells is accompanied by a dramatic inhibition of endocytosis.We have found that the addition of amphyphilic compounds to metaphase cells increases the endocytosis rate even to interphase levels.Detergents and solvents all increased endocytosis rate, and the extent of increase was in direct proportion to the concentration added.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.

ABSTRACT
Mitosis in mammalian cells is accompanied by a dramatic inhibition of endocytosis. We have found that the addition of amphyphilic compounds to metaphase cells increases the endocytosis rate even to interphase levels. Detergents and solvents all increased endocytosis rate, and the extent of increase was in direct proportion to the concentration added. Although the compounds could produce a variety of different effects, we have found a strong correlation with a physical alteration in the membrane tension as measured by the laser tweezers. Plasma membrane tethers formed by latex beads pull back on the beads with a force that was related to the in-plane bilayer tension and membrane- cytoskeletal adhesion. We found that as cells enter mitosis, the membrane tension rises as the endocytosis rate decreases; and as cells exited mitosis, the endocytosis rate increased as the membrane tension decreased. The addition of amphyphilic compounds decreased membrane tension and increased the endocytosis rate. With the detergent, deoxycholate, the endocytosis rate was restored to interphase levels when the membrane tension was restored to interphase levels. Although biochemical factors are clearly involved in the alterations in mitosis, we suggest that endocytosis is blocked primarily by the increase in apparent plasma membrane tension. Higher tensions inhibit both the binding of the endocytic complex to the membrane and mechanical deformation of the membrane during invagination. We suggest that membrane tension is an important regulator of the endocytosis rate and alteration of tension is sufficient to modify endocytosis rates during mitosis. Further, we postulate that the rise in membrane tension causes cell rounding and the inhibition of motility, characteristic of mitosis.

Show MeSH

Related in: MedlinePlus

Uptake of FM1-43 in interphase and metaphase cells  with increasing concentrations of deoxycholic acid. Nonsynchronized HeLa cells plated on a glass coverslips, labeled with FM1-43, treated 10 min with deoxycholic acid, fixed and stained with  DAPI, as described in Materials and Methods. Uptake of FM1-43 is expressed as a percentage of the value of interphase cells.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2132908&req=5

Figure 2: Uptake of FM1-43 in interphase and metaphase cells with increasing concentrations of deoxycholic acid. Nonsynchronized HeLa cells plated on a glass coverslips, labeled with FM1-43, treated 10 min with deoxycholic acid, fixed and stained with DAPI, as described in Materials and Methods. Uptake of FM1-43 is expressed as a percentage of the value of interphase cells.

Mentions: There are many practical reasons to want to increase fluid-phase uptake in mitotic cells, including the understanding of which factors may be primarily responsible for the decrease in endocytosis rate. A clear case where the rate of endocytosis is increased is after stimulated secretion. Secretory membrane that is added to the plasma membrane is rapidly recovered possibly because of membrane expansion. Amphyphilic compounds can also cause a significant increase in the area of plasma membranes. They could mimic the effect of secretion in expansion of the plasma membrane. When we added the detergent deoxycholate, we found that there was an increase in the membrane endocytosis rate of cells in metaphase (Fig. 2). As shown in Fig. 2, with increasing concentrations of deoxycholate, there was a proportional increase in the rate of endocytosis, indicating that the effect was proportional to detergent concentration. Endocytosis rates in mitotic cells reached interphase levels when 0.4 mM of deoxycholic acid was added which is still below the critical micelle concentration for deoxycholate. Thus, deoxycholic acid can cause a dramatic increase in the endocytosis rate even to interphase levels.


Membrane expansion increases endocytosis rate during mitosis.

Raucher D, Sheetz MP - J. Cell Biol. (1999)

Uptake of FM1-43 in interphase and metaphase cells  with increasing concentrations of deoxycholic acid. Nonsynchronized HeLa cells plated on a glass coverslips, labeled with FM1-43, treated 10 min with deoxycholic acid, fixed and stained with  DAPI, as described in Materials and Methods. Uptake of FM1-43 is expressed as a percentage of the value of interphase cells.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2132908&req=5

Figure 2: Uptake of FM1-43 in interphase and metaphase cells with increasing concentrations of deoxycholic acid. Nonsynchronized HeLa cells plated on a glass coverslips, labeled with FM1-43, treated 10 min with deoxycholic acid, fixed and stained with DAPI, as described in Materials and Methods. Uptake of FM1-43 is expressed as a percentage of the value of interphase cells.
Mentions: There are many practical reasons to want to increase fluid-phase uptake in mitotic cells, including the understanding of which factors may be primarily responsible for the decrease in endocytosis rate. A clear case where the rate of endocytosis is increased is after stimulated secretion. Secretory membrane that is added to the plasma membrane is rapidly recovered possibly because of membrane expansion. Amphyphilic compounds can also cause a significant increase in the area of plasma membranes. They could mimic the effect of secretion in expansion of the plasma membrane. When we added the detergent deoxycholate, we found that there was an increase in the membrane endocytosis rate of cells in metaphase (Fig. 2). As shown in Fig. 2, with increasing concentrations of deoxycholate, there was a proportional increase in the rate of endocytosis, indicating that the effect was proportional to detergent concentration. Endocytosis rates in mitotic cells reached interphase levels when 0.4 mM of deoxycholic acid was added which is still below the critical micelle concentration for deoxycholate. Thus, deoxycholic acid can cause a dramatic increase in the endocytosis rate even to interphase levels.

Bottom Line: Mitosis in mammalian cells is accompanied by a dramatic inhibition of endocytosis.We have found that the addition of amphyphilic compounds to metaphase cells increases the endocytosis rate even to interphase levels.Detergents and solvents all increased endocytosis rate, and the extent of increase was in direct proportion to the concentration added.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.

ABSTRACT
Mitosis in mammalian cells is accompanied by a dramatic inhibition of endocytosis. We have found that the addition of amphyphilic compounds to metaphase cells increases the endocytosis rate even to interphase levels. Detergents and solvents all increased endocytosis rate, and the extent of increase was in direct proportion to the concentration added. Although the compounds could produce a variety of different effects, we have found a strong correlation with a physical alteration in the membrane tension as measured by the laser tweezers. Plasma membrane tethers formed by latex beads pull back on the beads with a force that was related to the in-plane bilayer tension and membrane- cytoskeletal adhesion. We found that as cells enter mitosis, the membrane tension rises as the endocytosis rate decreases; and as cells exited mitosis, the endocytosis rate increased as the membrane tension decreased. The addition of amphyphilic compounds decreased membrane tension and increased the endocytosis rate. With the detergent, deoxycholate, the endocytosis rate was restored to interphase levels when the membrane tension was restored to interphase levels. Although biochemical factors are clearly involved in the alterations in mitosis, we suggest that endocytosis is blocked primarily by the increase in apparent plasma membrane tension. Higher tensions inhibit both the binding of the endocytic complex to the membrane and mechanical deformation of the membrane during invagination. We suggest that membrane tension is an important regulator of the endocytosis rate and alteration of tension is sufficient to modify endocytosis rates during mitosis. Further, we postulate that the rise in membrane tension causes cell rounding and the inhibition of motility, characteristic of mitosis.

Show MeSH
Related in: MedlinePlus