The cilium is a microtubule-based organelle that plays a pivotal role in embryonic development and maintenance of physiological functions in the human body. In addition to their function as sensors that transduce diverse extracellular signals, including growth factors, fluid flow, and physical forces, cilia are intricately involved in cell cycle regulation and preservation of DNA integrity, as their formation and resorption dynamics are tightly linked to cell cycle progression. Recently, several studies have linked defects in specific ciliary proteins to the DNA damage response.
View Article and Find Full Text PDFBackground: Motile cilia in a vertebrate are important to sustaining activities of life. Fluid flow on the apical surface of several tissues, including bronchial epithelium, ependymal epithelium, and fallopian tubules is generated by the ciliary beating of motile cilia. Multi-ciliated cells in ependymal tissue are responsible for the circulation of cerebrospinal fluid (CSF), which is essential for the development and homeostasis of the central nervous system, and airway tissues are protected from external contaminants by cilia-driven mucosal flow over the top of the airway epithelium.
View Article and Find Full Text PDFThe gap junction complex functions as a transport channel across the membrane. Among gap junction subunits, gap junction protein α1 (GJA1) is the most commonly expressed subunit. A recent study showed that GJA1 is necessary for the maintenance of motile cilia; however, the molecular mechanism and function of GJA1 in ciliogenesis remain unknown.
View Article and Find Full Text PDFBackground: Cell migration is a basic cellular behavior involved in multiple phenomena in the human body such as embryonic development, wound healing, immune reactions, and cancer metastasis. For proper cell migration, integrin and the ECM binding complex must be disassembled for the retraction of trailing edges.
Objective: Integrin must be differentially regulated at leading edges or trailing edges during cell migration.
Chondrocytes secrete massive extracellular matrix (ECM) molecules that are produced, folded, and modified in the endoplasmic reticulum (ER). Thus, the ER-associated degradation (ERAD) complex-which removes misfolded and unfolded proteins to maintain proteostasis in the ER- plays an indispensable role in building and maintaining cartilage. Here, we examined the necessity of the ERAD complex in chondrocytes for cartilage formation and maintenance.
View Article and Find Full Text PDFMotile cilia of multiciliated epithelial cells have important roles in animal development and cell homeostasis. Although several studies have identified and reported proteins localized in this complex organelle and the related immotile primary cilia from various cell types, it is still challenging to isolate high quantities of ciliary proteins for proteomic analysis. In this study, African clawed frog () embryos, which have many multiciliated cells in the epidermis, were treated with a simple ionic buffer to identify 1009 proteins conserved across vertebrates; these proteins were putatively localized in motile cilia.
View Article and Find Full Text PDFDeveloping and mature chondrocytes constantly interact with and remodel the surrounding extracellular matrix (ECM). Recent research indicates that integrin-ECM interaction is differentially regulated during cartilage formation (chondrogenesis). Integrin signaling is also a key source of the catabolic reactions responsible for joint destruction in both rheumatoid arthritis and osteoarthritis.
View Article and Find Full Text PDF