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Introduction The members of the annexin family of calcium- and phospholipid-binding proteins participate in different cellular processes (Gerke and Moss 2002; Rescher and Gerke 2004; Monastyrskaya et al. 2009). They [...], The members of the annexin family of calcium- and phospholipid-binding proteins participate in different cellular processes. Annexin A2 binds to S100A10, forming a functional heterotetrameric protein that has been involved in many cellular functions, such as exocytosis, endocytosis, cell junction formation, and actin cytoskeleton dynamics. Herein, we studied annexin A2 cellular movements and looked for its partners during epithelial cell differentiation. By using immunofluorescence, mass spectrometry (MS), and western blot analyses after S100A10 affinity column separation, we identified several annexin A2--S100A10 partner candidates. The association of putative annexin A2--S100A10 partner candidates obtained by MS after column affinity was validated by immunofluorescence and sucrose density gradient separation. The results show that three proteins are clearly associated with annexin A2: E-cadherin, actin, and caveolin 1. Overall, the data show that annexin A2 can associate with molecular complexes containing actin, caveolin 1, and flotillin 2 before epithelial differentiation and with complexes containing E-cadherin, actin, and caveolin 1, but not flotillin 2 after cell differentiation. The results indicate that actin, caveolin 1, and E-cadherin are the principal protein partners of annexin A2 in epithelial cells and that the serine phosphorylation of the N-terminal domain does not play an essential role during epithelial cell differentiation. Key words: actin, annexin A2, caveolin, epithelial cell differentiation, E-cadherin. Les membres de la famille des annexines, des protéines liant le calcium et les phospholipides, participent à différents processus cellulaires. L&apos;annexine A2 se lie à S100A10, formant une protéine hétérotétramérique fonctionnelle qui a été impliquée dans plusieurs fonctions cellulaires telles que l&apos;exocytose, l&apos;endocytose, la formation des jonctions cellulaires et la dynamique du cytosquelette. Les auteurs ont étudié ici les mouvements cellulaires de l&apos;annexine A2 et recherché ses partenaires durant la différenciation des cellules épithéliales. À l&apos;aide de l&apos;immunofluorescence, de la spectrométrie de masse et des analyses de transferts << western >> après séparation sur une colonne d&apos;affinité S100A10, ils ont identifié plusieurs candidats partenaires de l&apos;annexine A2--S100A10. L&apos;association de candidats partenaires présumés de l&apos;annexine A2--S100A10 obtenus par SM après la colonne d&apos;affinité a été validée par immunofluorescence et séparation sur un gradient de densité de sucrose. Les résultats montrent que trois protéines sont clairement associées à l&apos;annexine A2 : la E-cadhérine, l&apos;actine et la cavéoline 1. Globalement, les données montrent que l&apos;annexine A2 peut s&apos;associer à des complexes moléculaires comprenant l&apos;actine, la cavéoline et la flotilline 2 avant la différenciation épithéliale et à des complexes comprenant la E-cadhérine, l&apos;actine et la cavéoline 1, mais pas la flotilline 2, après la différenciation cellulaire. Les résultats indiquent que l&apos;actine, la cavéoline et la E-cadhérine constituent les principaux partenaires protéiques de l&apos;annexine A2 dans les cellules épithéliales et la phosphorylation des sérines du domaine N-terminal ne joue pas un rôle essentiel durant la différenciation des cellules épithéliales. [Traduit par la Rédaction] Mots-clés: actine, annexine A2, cavéoline, différenciation des cellules épithéliales, E-cadhérine.

A novel tetranuclear mu4(super -)eta(super 2):eta(super 2-)O,O carbonate nickel cluster with an S = 4 ground state is constructed by dinuclear building blocks of a predefined S = 2 pair state and a suitable cross-link ligand. The dinucleating Schiff base induces a ferromagnetic coupling per se between the metal centers allocated in each one of its N(sub 2)O(sub 2) pockets and these dinuclear units act as initial building blocks in construction of transition metal clusters of large S ground states using linking donors.

A simple route to isolate the tetranuclear complex [(Cu2L)2(CO3)] is described by self-assembly of dinuclear units and adventitious carbon dioxide. The crystal structure of the complex presents some unusual features, as the miscellaneous coordination polyhedra around the metal centers.

Serines at positions 11 and 25 are necessary for the aggregation of the monomeric and heterotetrameric forms of annexin 2. In the case of the monomer, sensitivity to Ca(super 2+) was also affected by mutations of these two residues but this effect was not seen in the heterotetramer.

A detailed characterization of peptide-membrane interactions of dermaseptin (Drs B2), which is a 33-residue-long cationic, [alpha]-helical antimicrobial peptide endowed with membrane-damaging activity against a wide range of microorganisms such as bacteria, yeast, fungi, and protozoa is described. The results showed that Drs B2 could adopt a flexible helix-hinge-helix structure in a membrane environment with a strong positive curvature strain that permits the concomitant insertion of the strongly hydrophobic N- and C-termini of the peptide into the acyl core of the membrane.