RhoGDI phosphorylation by PKC promotes its interaction with death receptor p75 to gate axon growth and neuron survival.

How receptors juggle their interactions with multiple downstream effectors remains poorly understood. Here we show that the outcome of death receptor p75 signaling is determined through competition of effectors for interaction with its intracellular domain, in turn dictated by the nature of the ligand. While NGF induces release of RhoGDI through recruitment of RIP2, thus decreasing RhoA activity in favor of NFkB signaling, MAG induces PKC-mediated phosphorylation of the RhoGDI N-terminus, promoting its interaction with the juxtamembrane domain of p75, disengaging RIP2, and enhancing RhoA activity in detriment of NF-kB.

Structural basis of NF-κB signaling by the p75 neurotrophin receptor interaction with adaptor protein TRADD through their respective death domains.

The p75 neurotrophin receptor (p75) is a critical mediator of neuronal death and tissue remodeling and has been implicated in various neurodegenerative diseases and cancers. The death domain (DD) of p75 is an intracellular signaling hub and has been shown to interact with diverse adaptor proteins. In breast cancer cells, binding of the adaptor protein TRADD to p75 depends on nerve growth factor and promotes cell survival.

LxCxD motif of the APC/C coactivator subunit FZR1 is critical for interaction with the retinoblastoma protein.

Retinoblastoma protein (pRB) regulates cell cycle by utilizing different regions of its pocket domain for interacting with E2F family of transcription factors and with cellular and viral proteins containing an LxCxE motif. An LxCxE-like motif, LxCxD, is present in FZR1, an adaptor protein of the multi-subunit E3 ligase complex anaphase-promoting complex/cyclosome (APC/C). The APC/C complex regulates the timely degradation of multiple cell cycle proteins for mitotic exit and maintains G1 state.

Inactive variants of death receptor p75 reduce Alzheimer's neuropathology by interfering with APP internalization.

A prevalent model of Alzheimer's disease (AD) pathogenesis postulates the generation of neurotoxic fragments derived from the amyloid precursor protein (APP) after its internalization to endocytic compartments. The molecular pathways that regulate APP internalization and intracellular trafficking in neurons are incompletely understood. Here, we report that 5xFAD mice, an animal model of AD, expressing signaling-deficient variants of the p75 neurotrophin receptor (p75 ) show greater neuroprotection from AD neuropathology than animals lacking this receptor.

APC/C and retinoblastoma interaction: cross-talk of retinoblastoma protein with the ubiquitin proteasome pathway.

The ubiquitin (Ub) ligase anaphase promoting complex/cyclosome (APC/C) and the tumour suppressor retinoblastoma protein (pRB) play key roles in cell cycle regulation. APC/C is a critical regulator of mitosis and G1-phase of the cell cycle whereas pRB keeps a check on proliferation by inhibiting transition to the S-phase. APC/C and pRB interact with each other via the co-activator of APC/C, FZR1, providing an alternative pathway of regulation of G1 to S transition by pRB using a post-translational mechanism.

Purification and biochemical characterization of methionine aminopeptidase (MetAP) from Mycobacterium smegmatis mc2155.

The methionine aminopeptidase (MetAP) catalyzes the removal of amino terminal methionine from newly synthesized polypeptide. MetAP from Mycobacterium smegmatis mc(2) 155 was purified from the culture lysate in four sequential steps to obtain a final purification fold of 22. The purified enzyme exhibited a molecular weight of approximately 37 kDa on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).