Structural and functional characterization of human Iba proteins.
نویسندگان
چکیده
Iba2 is a homolog of ionized calcium-binding adapter molecule 1 (Iba1), a 17-kDa protein that binds and cross-links filamentous actin (F-actin) and localizes to membrane ruffles and phagocytic cups. Here, we present the crystal structure of human Iba2 and its homodimerization properties, F-actin cross-linking activity, cellular localization and recruitment upon bacterial invasion in comparison with Iba1. The Iba2 structure comprises two central EF-hand motifs lacking bound Ca2+. Iba2 crystallized as a homodimer stabilized by a disulfide bridge and zinc ions. Analytical ultracentrifugation revealed a different mode of dimerization under reducing conditions that was independent of Ca2+. Furthermore, no binding of Ca2+ up to 0.1 mM was detected by equilibrium dialysis. Correspondingly, Iba EF-hand motifs lack residues essential for strong Ca2+ coordination. Sedimentation experiments and microscopy detected pronounced, indistinguishable F-actin binding and cross-linking activity of Iba1 and Iba2 with induction of F-actin bundles. Fluorescent Iba fusion proteins were expressed in HeLa cells and co-localized with F-actin. Iba1 was recruited into cellular projections to a larger extent than Iba2. Additionally, we studied Iba recruitment in a Shigella invasion model that induces cytoskeletal rearrangements. Both proteins were recruited into the bacterial invasion zone and Iba1 was again concentrated slightly higher in the cellular extensions.
منابع مشابه
Structural-functional studies of peptides derived from a long-chain snake neurotoxin Naja naja oxiana
Introduction: The design and structural characterization of mini-proteins with a compact, folded structure provide insight into the complex architecture of proteins today and has long been a challenging issue in structural- functional studies. Alpha neurotoxins from snake venom have a distinct folded structure comprised of a disulphide core and three loops or “fingers” each of these loops are c...
متن کاملMolecular and Phylogenetic Analysis and Protein Structural modeling of NS Gene of Human Influenza A Virus Subtype H1N1 Circulating in Iran 2015 & 2017
Abstract Background: The NS (non-structural) genomic segment of influenza A virus expresses two proteins (NS1 and NS2) which are responsible for the virulence and pathogenicity of virus. In this study we investigate the characterization and variability of the NS gene recovered from H1N1 influenza viruses isolated from Iranian patients during the 2017 seasonal outbreak and from high...
متن کاملFunctional Annotation of Two Hypothetical Proteins Reveals Valuable Proteins Involved in Response to Salinity: An in silico Approach
Through the exponential development in the specification of sequences and structures of proteins by genome sequencing and structural genomics approaches, there is a growing demand for valid bioinformatics methods to define these proteins function. In this study, our objective is to identify the function of unknown proteins from UCB-1 pistachio rootstock and specify their class...
متن کاملSynthesis and Functionalization of Gold Nanoparticles by Using of Poly Functional Amino Acids
Synthesis and characterization of two functionalized gold nanoparticles by using of two poly functional amino acids (L-Arginine and L-Aspartic acid) are reported. The gold nanoparticles were reduced by sodium citrate and functionalized with L-Arginine at the pH of 7 and 11 and L-Aspartic acid at the pH of 7. Transmission electron microscopy, UV-Vis spectroscopy, dynamic light scattering, zeta p...
متن کاملGlycation of Human IgG Induces Structural Alterations Leading to Changes in its Interaction with Anti-IgG
Background: Glycation of proteins is a non-enzymatic spontaneous process that occurs in diabetes mellitus and aging, altering the structure and function of proteins. IgG undergoes glycation leading to changes in its reactivity to antigen and fixation of complement. Objective: This study aimed at revealing the effect of glycation on the interaction of IgG with anti-IgG using electroimmunoassay...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- The FEBS journal
دوره 275 18 شماره
صفحات -
تاریخ انتشار 2008