Ndr/Lats Kinases Bind Specific Mob-Family Coactivators through a Conserved and Modular Interface

Area of Science:

• Cell Biology
• Structural Biology
• Biochemistry

Background:

• Hippo signaling pathways regulate cell proliferation and morphogenesis.
• Ndr/Lats kinases bind Mob coactivator proteins, forming essential complexes.
• Ndr/Lats kinases possess an N-terminal regulatory (NTR) region crucial for Mob cofactor interaction.

Purpose of the Study:

• To elucidate the structural basis of Ndr/Lats kinase-Mob cofactor association and specificity.
• To understand the regulatory mechanism mediated by the Ndr/Lats NTR-Mob interface.
• To identify the determinants of selective binding between Ndr/Lats kinases and distinct Mob cofactors.

Main Methods:

• Determined crystal structures of Saccharomyces cerevisiae Cbk1NTR-Mob2 and Dbf2NTR-Mob1 complexes.
• Experimentally assessed determinants of Mob cofactor binding and specificity.
• Analyzed the Ndr/LatsNTR-Mob interface and its interaction with the AGC kinase C-terminal hydrophobic motif (HM).

Main Results:

• The Ndr/LatsNTR-Mob interface organizes the NTR to interact with the AGC kinase HM for allosteric regulation.
• The Mob-organized NTR mediates HM association with an allosteric site on the N-terminal kinase lobe.
• Cofactor specificity is determined by discrete sites within the Ndr/Lats NTR, as demonstrated by altering residues to allow noncognate Mob binding.

Conclusions:

• The Ndr/LatsNTR-Mob interface is a common structural platform for kinase-cofactor binding.
• Mob cofactors play a critical role in organizing Ndr/Lats kinase regulation via the NTR.
• Specific binding sites within the NTR dictate cofactor specificity, providing a mechanism for pathway regulation.