The Primary Cilium as a Complex Signaling Center

Abstract

Respect for the primary cilium has undergone a remarkable renaissance over the past decade, and it is now thought to be an essential regulator of numerous signaling pathways. The primary cilium’s functions range from the movement of cells and fluid, to sensory inputs involved with olfaction and photoreception. Disruption of cilia function is involved in multiple human syndromes collectively called ‘ciliopathies’. The cilium’s activities are mediated by targeting of receptors, channels, and their downstream effector proteins to the ciliary or basal body compartment. These combined properties of the cilium make it a critical organelle facilitating the interactions between the cell and its environment. Here we review many of the recent advances contributing to the ascendancy of the primary cilium and how the extraordinary complexity of this organelle inevitably assures many more exciting future discoveries.

CPAP promotes timely cilium disassembly to maintain neural progenitor pool

“…During interphase, the centriole within a centrosome nucleates the formation of the primary cilium, which is known to play key roles in signaling pathways (Berbari et al , 2009; Nigg & Raff, 2009; Jackson, 2011). The cilium is the primary microtubule‐based organelle that is dynamically regulated, with assembly occurring during cell cycle exit, and disassembly coinciding with cell cycle re‐entry (Jackson, 2011; Kim et al , 2011; Paridaen et al , 2013; Guemez‐Gamboa et al , 2014).…”

Effect of in vitro stress‐deprivation and cyclic loading on the length of tendon cell cilia in situ

“…Keywords: tendon cell; primary cilia; stress-deprivation; tensile loading Mechanical loading is essential for maintaining the health and homeostasis of tendons, although the fundamental mechanotransduction pathways by which cells mediate this process are unclear. 1 Primary cilia are sensory organelles for the detection and transmission of mechanical and chemical information from the extracellular environment of cells [2][3][4] and are known to function as mechanosensors in several connective tissue cell types, including tenocytes, osteocytes, and chondrocytes. [5][6][7][8][9][10][11] The expression of transmembrane extracellular matrix receptors (integrins) on the cilium strongly suggests that the cilium has the molecular machinery necessary to act as a mechanosensory linkage between the ECM and cytoplasmic organelles.…”

Present Status and Advances in Autosomal Dominant Polycystic Kidney Disease

“…Primary cilia are microtubule-based antenna-like organelles protruding from the surface of vertebrate cells that mediate a number of signaling pathways during development and tissue homeostasis [32]. Defects in primary cilia are thought to play an important role in polycystic kidney disease [46,47].…”

“…Polycystin-1 is found in most segments of the nephron and is distributed in a variety of subcellular structures such as the primary cilia, cytoplasmic vesicles, plasma membrane at focal adhesions, desmosomes, adherens junctions, and possibly endoplasmic reticulum and nuclei. Among them, polycystin-1 distributed in primary cilia is considered to play an important role in the mechano/chemo-sensor function [32][33][34], whereas polycystin-1 distributed in the side wall and the basal body participates in the formation of intercellular adhesion and focal adhesion [35]. In addition, a cleavage product of polycystin-1 that includes the C-terminal tail can translocate to the nucleus and regulate gene transcription [36,37].…”