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Novel perspectives on the transcytotic route in osteoclasts.

Hirvonen MJ, Fagerlund K, Lakkakorpi P, Väänänen HK, Mulari MT - Bonekey Rep (2013)

Bottom Line: Helix pomatia lectin binding indicated that transcytotic vesicles expose aberrant N-acetylgalactosamine glycoconjugates, which is associated with a poor prognosis for a range of metastasizing human adenocarcinomas.Transcytotic vesicles fuse with the autophagosomal compartments and represent raft concentrates.Finally, our data suggest that the targeting of these membrane pathways may be determined by a novel F-actin-containing and FSD-circumscribing molecular barrier.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology and Anatomy, Institute of Biomedicine, University of Turku , Turku, Finland.

ABSTRACT
We analyzed the characteristics of degraded bone matrix-delivering vesicles along the transcytotic route from the ruffled border to the functional secretory domain (FSD) in bone-penetrating osteoclasts. Cells of rat or human origin were cultured on bovine bone slices and analyzed via confocal microscopy. Helix pomatia lectin binding indicated that transcytotic vesicles expose aberrant N-acetylgalactosamine glycoconjugates, which is associated with a poor prognosis for a range of metastasizing human adenocarcinomas. Transcytotic vesicles fuse with the autophagosomal compartments and represent raft concentrates. Furthermore, the results of a vertical vesicle analysis suggest that multiple vesicle populations arise from the ruffled border and that some of these vesicles undergo a maturation process along the transcytotic route. Finally, our data suggest that the targeting of these membrane pathways may be determined by a novel F-actin-containing and FSD-circumscribing molecular barrier.

No MeSH data available.


Related in: MedlinePlus

A schematic summarizing the major findings of the current paper. Osteoclast degrades bone by secretion of acid and proteolytic enzymes to the resorption lacuna at the peripheral fusion zone of the ruffled border (blue arrows). Bone degradation products are endocytozed from the resorption lacuna at the central uptake zone of the ruffled border and delivered to the FSD via transcytosis. Multiple types of transcytotic vesicles that are formed initially at the ruffled border level follow their distinct routes to the FSD (green arrows). FSD is circumscribed by a thin actin-based barrier (red circles).
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f5: A schematic summarizing the major findings of the current paper. Osteoclast degrades bone by secretion of acid and proteolytic enzymes to the resorption lacuna at the peripheral fusion zone of the ruffled border (blue arrows). Bone degradation products are endocytozed from the resorption lacuna at the central uptake zone of the ruffled border and delivered to the FSD via transcytosis. Multiple types of transcytotic vesicles that are formed initially at the ruffled border level follow their distinct routes to the FSD (green arrows). FSD is circumscribed by a thin actin-based barrier (red circles).

Mentions: In conclusion, the osteoclastic transcytotic route from the ruffled border to the FSD is thus far poorly characterized. We demonstrated that multiple types of transcytotic vesicles arise from the ruffled border and deliver the bone degradation products for exocytosis. These vesicles are transported to the FSD that is circumscribed and separated from the peripheral non-bone-facing plasma membrane by an actin-based molecular barrier (Figure 5). Specific details of transcytosis in osteoclasts, for example, the regulatory molecules, such as small GTPases, however, remain yet to be elucidated.


Novel perspectives on the transcytotic route in osteoclasts.

Hirvonen MJ, Fagerlund K, Lakkakorpi P, Väänänen HK, Mulari MT - Bonekey Rep (2013)

A schematic summarizing the major findings of the current paper. Osteoclast degrades bone by secretion of acid and proteolytic enzymes to the resorption lacuna at the peripheral fusion zone of the ruffled border (blue arrows). Bone degradation products are endocytozed from the resorption lacuna at the central uptake zone of the ruffled border and delivered to the FSD via transcytosis. Multiple types of transcytotic vesicles that are formed initially at the ruffled border level follow their distinct routes to the FSD (green arrows). FSD is circumscribed by a thin actin-based barrier (red circles).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3722746&req=5

f5: A schematic summarizing the major findings of the current paper. Osteoclast degrades bone by secretion of acid and proteolytic enzymes to the resorption lacuna at the peripheral fusion zone of the ruffled border (blue arrows). Bone degradation products are endocytozed from the resorption lacuna at the central uptake zone of the ruffled border and delivered to the FSD via transcytosis. Multiple types of transcytotic vesicles that are formed initially at the ruffled border level follow their distinct routes to the FSD (green arrows). FSD is circumscribed by a thin actin-based barrier (red circles).
Mentions: In conclusion, the osteoclastic transcytotic route from the ruffled border to the FSD is thus far poorly characterized. We demonstrated that multiple types of transcytotic vesicles arise from the ruffled border and deliver the bone degradation products for exocytosis. These vesicles are transported to the FSD that is circumscribed and separated from the peripheral non-bone-facing plasma membrane by an actin-based molecular barrier (Figure 5). Specific details of transcytosis in osteoclasts, for example, the regulatory molecules, such as small GTPases, however, remain yet to be elucidated.

Bottom Line: Helix pomatia lectin binding indicated that transcytotic vesicles expose aberrant N-acetylgalactosamine glycoconjugates, which is associated with a poor prognosis for a range of metastasizing human adenocarcinomas.Transcytotic vesicles fuse with the autophagosomal compartments and represent raft concentrates.Finally, our data suggest that the targeting of these membrane pathways may be determined by a novel F-actin-containing and FSD-circumscribing molecular barrier.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology and Anatomy, Institute of Biomedicine, University of Turku , Turku, Finland.

ABSTRACT
We analyzed the characteristics of degraded bone matrix-delivering vesicles along the transcytotic route from the ruffled border to the functional secretory domain (FSD) in bone-penetrating osteoclasts. Cells of rat or human origin were cultured on bovine bone slices and analyzed via confocal microscopy. Helix pomatia lectin binding indicated that transcytotic vesicles expose aberrant N-acetylgalactosamine glycoconjugates, which is associated with a poor prognosis for a range of metastasizing human adenocarcinomas. Transcytotic vesicles fuse with the autophagosomal compartments and represent raft concentrates. Furthermore, the results of a vertical vesicle analysis suggest that multiple vesicle populations arise from the ruffled border and that some of these vesicles undergo a maturation process along the transcytotic route. Finally, our data suggest that the targeting of these membrane pathways may be determined by a novel F-actin-containing and FSD-circumscribing molecular barrier.

No MeSH data available.


Related in: MedlinePlus