Coiled-coil domains of intermediate filaments (IF) and prokaryotic IF-like proteins enable oligomerisation and filamentation, and no additional function is ascribed to these coiled-coil domains. However, an IF-like protein from Streptomyces reticuli was reported to display cellulose affinity. We demonstrate that cellulose affinity is an intrinsic property of the IF-like proteins FilP and Scy and the coiled-coil protein DivIVA from the genus Streptomyces. Furthermore, IF-like proteins and DivIVA from other prokaryotic species and metazoan IF display cellulose affinity despite having little sequence homology. Cellulose affinity-based purification is utilised to isolate native FilP protein from the whole cell lysate of S. coelicolor. Moreover, cellulose affinity allowed for the isolation of IF and IF-like protein from the whole cell lysate of C. crescentus and a mouse macrophage cell line. The binding to cellulose is mediated by certain combinations of coiled-coil domains, as demornstrated for FilP and lamin. Fusions of target proteins to cellulose-binding coiled-coil domains allowed for cellulose-based protein purification. The data presented show that cellulose affinity is a novel function of certain coiled-coil domains of IF and IF-like proteins from evolutionary diverse species.

BackgroundAlzheimer’s disease (AD) and cholesterol homeostasis have long been linked, most notably by the identification of apolipoprotein E‐ε4 allele as the strongest risk factor. Yet the mechanism by which its pathogenic isoform ε4 impacts AD has remained elusive. Different GWA studies have identified other potential risk factors, many of which are also involved in the maintenance, homeostasis, mobilisation, and distribution of cholesterol. The aim of this study was to analyse three candidate genes involved in cholesterol metabolism, which showed preliminary significance and are strongly related to cholesterol processes and APOE neurobiology.MethodThe three candidates are the receptors LDLR, VLDLR and APOBR which were analysed using neocortical mRNA data from the Religious Orders study/ Memory and Aging Project ROSMAP cohort’s dataset. The receptor mRNA levels were contrasted against several AD pathological markers, such as Braak and CERAD stages. Other apolipoprotein mRNA levels were also analysed for significance. Age, Sex and ApoE4 genotype were also tested for effect.ResultPreliminary analyses showed significant correlation between mRNA levels of these receptors (most strongly VLDLR) and Braak stages (VLDLR p < 0.008), CERAD stages (VLDLR p < 0.001) as well as several proteins known to be involved in AD pathophysiology. VLDLR expression levels did not correlate with APOE mRNA levels (VLDLR; R2=0.176, p > 0.05) and were only significant in APOε4 negative subjects when split for APOε4 genotype (VLDLR Braak p < 0.003).ConclusionThe three receptors analysed so far appear to be involved at some level with AD pathophysiology. They will be further studied and investigated in both, symptomatic and pre‐symptomatic AD. The relationship between the receptors and APOE pathophysiology in sporadic AD remains unclear.