NAC controls cotranslational N-terminal methionine excision in eukaryotes

N-terminal methionine excision from newly synthesized proteins, catalyzed cotranslationally by methionine aminopeptidases (METAPs), is an essential and universally conserved process that plays a key role in cell homeostasis and protein biogenesis. However, how METAPs interact with ribosomes and how their cleavage specificity is ensured is unknown. We discovered that in eukaryotes the nascent polypeptide-associated complex (NAC) controls ribosome binding of METAP1. NAC recruits METAP1 using a long, flexible tail and provides a platform for the formation of an active methionine excision complex at the ribosomal tunnel exit. This mode of interaction ensures the efficient excision of methionine from cytosolic proteins, whereas proteins targeted to the endoplasmic reticulum are spared. Our results suggest a broader mechanism for how access of protein biogenesis factors to translating ribosomes is controlled.

Synthesis and biological evaluation of novel (4 or 5-aryl)pyrazolyl-indoles as inhibitors of interleukin-2 inducible T-cell kinase (ITK)

Interleukin-2 inducible T-cell kinase (ITK) is one of five kinases that belong to the Tec kinase family that plays an important role in T-cell and mast cell signaling. Various reports point to a role of ITK in the treatment of allergic asthma. For example, it was shown that mice lacking ITK have reduced airway hyperresponsiveness, inflammation and tracheal responses in an allergic asthma model. In this article, we disclose novel ITK inhibitors based on (4 or 5-aryl)pyrazolyl-indole scaffold that were also found to be selective for ITK over other kinases like IRK, CDK2, GSK3ss and PKA.