RASopathy mutations provide functional insight into the BRAF cysteine-rich domain and reveal the importance of autoinhibition in BRAF regulation

Author:

Smith,Russell

Terrell,Elizabeth

Insinna, Christine

Agamasu, Constance

Wagner, Morgan E

Ritt,Daniel

Stauffer,Jimmy

Stephen,Andy

Morrison,Deborah
Author Address

Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702 USA., National Cancer Institute RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Leidos Biomedical Research, Inc., Frederick, MD 21702 USA., Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702 USA. Electronic address: morrisod@mail.nih.gov.,

Abstract:

BRAF is frequently mutated in human cancer and the RASopathy syndromes, with RASopathy mutations often observed in the cysteine-rich domain (CRD). Although the CRD participates in phosphatidylserine (PS) binding, the RAS-RAF interaction, and RAF autoinhibition, the impact of these activities on RAF function in normal and disease states is not well characterized. Here, we analyze a panel of CRD mutations and show that they increase BRAF activity by relieving autoinhibition and/or enhancing PS binding, with relief of autoinhibition being the major factor determining mutation severity. Further, we show that CRD-mediated autoinhibition prevents the constitutive plasma membrane localization of BRAF that causes increased RAS-dependent and RAS-independent function. Comparison of the BRAF- and CRAF-CRDs also indicates that the BRAF-CRD is a stronger mediator of autoinhibition and PS binding, and given the increased catalytic activity of BRAF, our studies reveal a more critical role for CRD-mediated autoinhibition in BRAF regulation. Published by Elsevier Inc.

See More

Author Address