Distribution of actin filaments, non-muscle myosin, M-Ras, and extracellular signal-regulated kinase (ERK) in osteoclasts after calcitonin administration

Hiroaki Nakamura, Noriyuki Nagaoka, Azumi Hirata, Miho Inoue, Hidehiro Ozawa, Toshio Yamamoto

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Scanning electron microscopy (SEM) was employed to study the effect of calcitonin on the distribution of actin filaments in osteoclasts obtained from rat tibiae. Fluorescent microscopy was also applied to examine calcitonin-induced changes in the distribution of actin filaments, non-muscle myosin, M-Ras, and extracellular signal-regulated kinase (ERK) to clarify the role of ERK in the cytoskeleton of osteoclasts. SEM of control osteoclasts revealed a ring-like structure in the peripheral region. Labeled actin filaments and non-muscle myosin were detected in the peripheral region and exhibited a ring-like pattern. Immunoreactivity indicating M-Ras and ERK was also detected in the vicinity of the actin ring. After calcitonin treatment, many osteoclasts exhibited a retracted appearance and lacked a discernible actin ring. Numerous retraction fibers were found at the edge of calcitonin-treated osteoclasts. Actin filaments and non-muscle myosin were concentrated in the cytoplasm of calcitonin-treated osteoclasts, and exhibited a filamentous pattern. Labeled M-Ras and ERK also accumulated in the central region of these osteoclasts. These findings suggest that actin-myosin interaction plays an essential role in the retraction of osteoclasts induced by calcitonin. ERK may play a role in this interaction by activating myosin light chain kinase, as previously observed in smooth muscle cells.

Original languageEnglish
Pages (from-to)143-150
Number of pages8
Journalarchives of histology and cytology
Volume68
Issue number2
DOIs
Publication statusPublished - Jan 1 2005

ASJC Scopus subject areas

  • Histology

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