31Vertebrate vision is accomplished through a set of light-sensitive photopigments, which 32 are located in the photoreceptors of the retina and consist of a visual opsin protein bound 33 to a chromophore. In dim-light, vertebrates generally rely upon a single rod opsin (RH1) 34 for obtaining visual information. By inspecting 101 fish genomes, we found that three 35 deep-sea teleost lineages have independently expanded their RH1 gene repertoires. 36 Amongst these, the silver spinyfin (Diretmus argenteus Johnson 1863) stands out as having 37 the highest number of visual opsins known for animals to date (2 cone and 38 rod opsins). 38 Spinyfins simultaneously express up to 14 RH1s encoding for photopigments with 39 different peak spectral sensitivities (λmax=448-513 nm) that cover the range of the residual 40 daylight, as well as the bioluminescence spectrum present in the deep-sea. Our findings 41 present novel molecular and functional evidence for the recurrent evolution of multiple 42 rod opsin-based vision in vertebrates. 43 44 SHORT ABSTRACT: Contrary to the single rod opsin used by most vertebrates, some fishes 45 use multiple rod opsins for vision in the dimly lit deep-sea. 46 Animals use vision for a variety of fundamental tasks including navigation, food acquisition, 47

Vertebrate vision is accomplished through light-sensitive photopigments consisting of an opsin protein bound to a chromophore. In dim-light, vertebrates generally rely upon a single rod opsin (RH1) for obtaining visual information. By inspecting 101 fish genomes, we found that three deep-sea teleost lineages have independently expanded their RH1 gene repertoires. Amongst these, the silver spinyfin (Diretmus argenteus) stands out as having the highest number of visual opsins in vertebrates (2 cone, 38 rod opsins). Spinyfins express up to 14 RH1s (including the most blue-shifted rod photopigments known), which cover the range of the residual daylight as well as the bioluminescence spectrum present in the deep sea. Our findings present molecular and functional evidence for the recurrent evolution of multiple rod opsin-based vision in vertebrates.

PI3KC2a is a broadly expressed lipid kinase with critical functions during embryonic development but poorly defined roles in adult physiology. Here we utilize multiple mouse genetic models to uncover a role for PI3KC2a in regulating the internal membrane reserve structure of megakaryocytes (demarcation membrane system) and platelets (open canalicular system) that results in dysregulated platelet adhesion under haemodynamic shear stress. Structural alterations in the platelet internal membrane lead to enhanced membrane tether formation that is associated with accelerated, yet highly unstable, thrombus formation in vitro and in vivo. Notably, agonist-induced 3-phosphorylated phosphoinositide production and cellular activation are normal in PI3KC2a-deficient platelets. These findings demonstrate an important role for PI3KC2a in regulating shear-dependent platelet adhesion via regulation of membrane structure, rather than acute signalling. These studies provide a link between the open canalicular system and platelet adhesive function that has relevance to the primary haemostatic and prothrombotic function of platelets.