Proteomic Analysis of Mammalian Primary Cilia

Abstract

Summary The primary cilium is a microtubule-based organelle that senses extracellular signals as a cellular antenna [1]. Primary cilia are found on many types of cells in our body and play important roles in development and physiology. Defects of primary cilia cause a broad class of human genetic diseases called ciliopathies. To gain new insights into ciliary functions and better understand the molecular mechanisms underlying ciliopathies, it is of high importance to generate a catalog of primary cilia proteins. In this study, we isolated primary cilia from mouse kidney cells by using a calcium shock method and identified 195 candidate primary cilia proteins by MudPIT (multidimensional protein identification technology), protein correlation profiling, and subtractive proteomic analysis. Based on comparisons with other proteomic studies of cilia, around 75% of our candidate primary cilia proteins are shared components with motile or specialized sensory cilia. The remaining 25% of the candidate proteins are possible primary cilia specific proteins. These possible primary cilia specific proteins include Evc2, Inpp5e and Inversin, several of which have been linked to known ciliopathies. We have performed the first reported proteomic analysis of primary cilia from mammalian cells. These results provide new insights into primary cilia structure and function.

Proteomic analysis of mammalian sperm cells identifies new components of the centrosome

“…A combination of proteomic, bioinformatic and genomic approaches (Ostrowski et al, 2002;Avidor-Reiss et al, 2004;Li et al, 2004;Keller et al, 2005;Kilburn et al, 2007;McClintock et al, 2008;Keller et al, 2009;Jakobsen et al, 2011;Hoh et al, 2012;Ishikawa et al, 2012) has identified many centrosome and cilium proteins. The centriole proteomes of Chlamydomonas (Keller et al, 2005) and Tetrahymena (Kilburn et al, 2007) have been analyzed, but direct proteomic analysis of mammalian centrioles has not been reported.…”

Regulation of polycystin-1 ciliary trafficking by motifs at its C-terminus and polycystin-2 but not cleavage at GPS site

“…In addition, PC2 is considered as an endoplasmic reticulum (ER)-resident protein where it might also mediate Ca 2+ release from ER (Koulen et al, 2002). To date, proteomic studies have revealed the presence of hundreds of polypeptides inside the cilium (Gherman et al, 2006;Ishikawa et al, 2012). The mechanism by which these proteins are targeted to cilia, however, remains poorly understood.…”

Primary cilia enhance kisspeptin receptor signaling on gonadotropin-releasing hormone neurons

“…Hypogonadotropic hypogonadism is a typical clinical feature of Bardet-Biedl syndrome, a human ciliopathy. Another putative link is suggested by the finding that WDR11, which is mutated in patients with hypogonadotropic hypogonadism (52), is present within primary cilia (53). However, our results indicate that disruption of GnRH neuronal cilia structure is not sufficient to prevent normal sexual maturation in mice.…”