Mechanistic Insights of an Immunological Adverse Event Induced by an Anti-KIT Antibody Drug Conjugate and Mitigation Strategies.

Hypersensitivity reactions (HSRs) were observed in three patients dosed in a phase I clinical trial treated with LOP628, a KIT targeted antibody drug conjugate. Mast cell degranulation was implicated as the root cause for the HSR. Underlying mechanism of this reported HSR was investigated with an aim to identifying potential mitigation strategies.

Immunoglobulin domain interface exchange as a platform technology for the generation of Fc heterodimers and bispecific antibodies.

Bispecific antibodies (bsAbs) are of significant importance to the development of novel antibody-based therapies, and heavy chain (Hc) heterodimers represent a major class of bispecific drug candidates. Current technologies for the generation of Hc heterodimers are suboptimal and often suffer from contamination by homodimers posing purification challenges. Here, we introduce a new technology based on biomimicry wherein the protein-protein interfaces of two different immunoglobulin (Ig) constant domain pairs are exchanged in part or fully to design new heterodimeric domains.

Conformational dynamics of helix 8 in the GPCR rhodopsin controls arrestin activation in the desensitization process.

Arrestins are regulatory molecules for G-protein coupled receptor function. In visual rhodopsin, selective binding of arrestin to the cytoplasmic side of light-activated, phosphorylated rhodopsin (P-Rh*) terminates signaling via the G-protein transducin. While the "phosphate-sensor" of arrestin for the recognition of receptor-attached phosphates is identified, the molecular mechanism of arrestin binding and the involvement of receptor conformations in this process are still largely hypothetic.

A rationally designed monomeric variant of anthranilate phosphoribosyltransferase from Sulfolobus solfataricus is as active as the dimeric wild-type enzyme but less thermostable.

The anthranilate phosphoribosyltransferase from Sulfolobus solfataricus (ssAnPRT) forms a homodimer with a hydrophobic subunit interface. To elucidate the role of oligomerisation for catalytic activity and thermal stability of the enzyme, we loosened the dimer by replacing two apolar interface residues with negatively charged residues (mutations I36E and M47D). The purified double mutant I36E+M47D formed a monomer with wild-type catalytic activity but reduced thermal stability.

Lamina-associated polypeptide 2-alpha forms homo-trimers via its C terminus, and oligomerization is unaffected by a disease-causing mutation.

The nucleoplasmic protein, Lamina-associated polypeptide (LAP) 2alpha, is one of six alternatively spliced products of the LAP2gene, which share a common N-terminal region. In contrast to the other isoforms, which also share most of their C termini, LAP2alpha has a large unique C-terminal region that contains binding sites for chromatin, A-type lamins, and retinoblastoma protein. By immunoprecipitation analyses of LAP2alpha complexes from cells expressing differently tagged LAP2alpha proteins and fragments, we demonstrate that LAP2alpha forms higher order structures containing multiple LAP2alpha molecules in vivo and that complex formation is mediated by the C terminus.

N-terminal and C-terminal domains of arrestin both contribute in binding to rhodopsin.

Visual arrestin terminates the signal amplification cascade in photoreceptor cells by blocking the interaction of light activated phosphorylated rhodopsin with the G-protein transducin. Although crystal structures of arrestin and rhodopsin are available, it is still unknown how the complex of the two proteins is formed. To investigate the interaction sites of arrestin with rhodopsin various surface regions of recombinant arrestin were sterically blocked by different numbers of fluorophores (Alexa 633).