Ascidian arrestin (Ci‐arr), the origin of the visual and nonvisual arrestins of vertebrate

Abstract

Arrestin is one of the key proteins for the termination of G protein signaling. Activated G protein-coupled receptors (GPCRs) are specifically phosphorylated by G proteincoupled receptor kinases (GRKs) and then bind to arrestins to preclude the receptor/G protein interaction, resulting in quenching of the following signal transduction. Vertebrates possess two types of arrestin; visual arrestin expressed exclusively in photoreceptor cells in retinae and pineal organs, and b-arrestin, which is expressed ubiquitously. Unlike visual arrestin, b-arrestin contains the clathrinbinding domain at the C-terminus, responsible for the agonist-induced internalization of GPCRs. Here, we isolated a novel arrestin gene (Ci-arr) from the primitive chordate, the ascidian Ciona intestinalis larvae. The deduced amino acid sequence suggests that Ci-Arr be closely related to vertebrate arrestins. Interestingly, this arrestin has the feature of both visual and b-arrestin. Whereas the expression of Ci-arr was restricted to the photoreceptors in the larvae similarly to visual arrestin, the gene product, containing the clathrin-binding domain, promoted the GPCR internalization in HEK293tsA201 cells similarly to b-arrestin. The phylogenetic tree shows that Ci-Arr is branched from a common root of visual and b-arrestins. Southern analysis suggests that the Ciona genome contains only one gene for the arrestin family. These results suggest that the visual and b-arrestin genes were generated by the duplication of the prototypical arrestin gene like Ci-arr in the early evolution of vertebrates.

Morpholino-based gene knockdown screen of novel genes with developmental function inCiona intestinalis

“…The probes used were Ci-Epi1 for epidermal cell differentiation (Chiba et al, 1998), Ci-ETR for nervous system development (Satou et al, 2001b), Ci-talin for notochord differentiation (Satou et al, 2001b;Sasakura et al, 2003) and ciad005j06 for mesenchyme cell differentiation (Satou et al, 2001b). Probes for Ci-arr (Nakagawa et al, 2002), Ci-opsin1 (Kusakabe et al, 2001), Ci-opsin3 (Nakashima et al, 2003) and Ci-Gαi1a were also used for experiments with the citb018a19 gene.…”

FGF/MAPK/Ets signaling renders pigment cell precursors competent to respond to Wnt signal by directly controllingCi-Tcftranscription

“…Functional similarities and conservation of basic gene expression patterns led to infer that ascidian sensory organs, vertebrate eye and pineal organ could be derived from a common archetypal 'visual organ' (Kusakabe et al, 2001;Sato and Yamamoto, 2001;Lamb et al, 2007). Molecules belonging to arrestin and opsin classes are expressed in ocellus photoreceptors as in vertebrate retina photoreceptor cells and pineal organ (Kusakabe et al, 2001;Nakagawa et al, 2002;Nakashima et al, 2003). Ascidian sensory organ pigment cells, analogously to the vertebrate RPE, pineal gland and melanocytes (Tief et al, 1996), express the melanogenic genes tyrosinase (tyr) (Caracciolo et al, 1997) and tyrosinase related protein (tyrp) (Toyoda et al, 2004).…”

Development of swimming behaviour in the larva of the ascidianCiona intestinalis

“…The ocellus is a pigmented cell associated with 17-30 photoreceptor cells and a lens (Eakin and Kuda, 1971;Nicol and Meinertzhagen, 1991;Horie et al, 2005). The otolith is a single pigmented cell, connected to neurones via the floor of the sensory vesicle (Tsuda et al, 2003a;Nagakawa et al, 2002;Sakurai et al, 2004). These two organs are mainly involved in the perception of environmental cues that drive ascidian tadpole behaviour (Tsuda et al, 2003a;Sakurai et al, 2004;Di Jiang et al, 2005).…”