Department of Ecology, Environment and Evolution , La Trobe University , Melbourne , VIC 3086 , Australia.
Centre for Sustainable Tropical Fisheries and Aquaculture , James Cook University , Townsville , QLD 4811 , Australia.
J Proteome Res. 2019 Mar 1;18(3):890-899. doi: 10.1021/acs.jproteome.8b00569. Epub 2019 Jan 25.
Sepioloidea lineolata, the striped pyjama squid (family Sepiadariidae), is a small species of benthic bobtail squid distributed along the Southern Indo-Pacific coast of Australia. Like other sepiadariid squids, it is known to secrete large volumes of viscous slime when stressed. In order to identify key proteins involved in the function of sepiadariid slimes, we compared the slime proteome of Sepioloidea lineolata with that of a closely related species, Sepiadarium austrinum. Of the 550 protein groups identified in Sepioloidea lineolata slime, 321 had orthologs in Sepiadarium austrinum, and the abundance of these (iBAQ) was highly correlated between species. Both slimes were dominated by a small number of abundant proteins, and several of these were short secreted proteins with no homologues outside the class Cephalopoda. No mucins were identified within either species' slime, suggesting that it is structurally distinct from mucin polymer-based gels found in many vertebrate and echinoderm secretions. The extent of N-glycosylation in the slime of Sepioloidea lineolata was also studied via glycan cleavage with Peptide: N-glycosidase F (PNGase-F). Although very few (four) proteins showed strong evidence of N-glycosylation, we found that treatment with PNGase-F led to a slight increase in peptide identification rates compared with controls.
条纹睡衣鱿鱼（Sepiadariidae 科），又名线纹枪乌贼，是一种分布于澳大利亚南部印度-太平洋沿岸的小型底栖短尾鱿鱼。与其他枪形目鱿鱼一样，当受到压力时，它会分泌大量粘性黏液。为了鉴定参与枪形目鱿鱼黏液功能的关键蛋白，我们比较了条纹睡衣鱿鱼和与之密切相关的物种 Sepiadarium austrinum 的黏液蛋白质组。在条纹睡衣鱿鱼的黏液中鉴定出的 550 个蛋白质组中，有 321 个在 Sepiadarium austrinum 中有同源物，这些蛋白质的丰度（iBAQ）在物种间高度相关。两种黏液都由少数丰富的蛋白质组成，其中一些是短分泌蛋白，在头足类动物以外的类群中没有同源物。在这两个物种的黏液中都没有鉴定出粘蛋白，这表明它的结构与许多脊椎动物和棘皮动物分泌物中基于粘蛋白聚合物的凝胶不同。我们还通过肽：N-糖基化酶 F（PNGase-F）的糖链切割研究了条纹睡衣鱿鱼黏液中的 N-糖基化程度。尽管只有少数（四个）蛋白质表现出强烈的 N-糖基化证据，但我们发现与对照相比，用 PNGase-F 处理会略微增加肽鉴定率。
