7NQC

Calmodulin extracts the Ras family protein RalA from lipid bilayers by engagement with two membrane targeting motifs

Summary for 7NQC

• Entry DOI: 10.2210/pdb7nqc/pdb
• NMR Information: BMRB: 34608
• Descriptor: Calmodulin-1, PRO-ASN-GLY-LYS-LYS-LYS-ARG-LYS-SER-LEU-ALA-LYS-ARG-ILE-ARG-GLU-ARG-CMF, CALCIUM ION, ... (4 entities in total)
• Functional Keywords: farnesylation; calcium binding, signaling protein
• Biological source: Rattus norvegicus (Rat); More
• Total number of polymer chains: 2
• Total formula weight: 21287.94

Authors

Chamberlain, S.G.,Owen, D.,Mott, H.R. (deposition date: 2021-03-01, release date: 2021-09-22, Last modification date: 2024-11-06)

Primary citation

Chamberlain, S.G.,Gohlke, A.,Shafiq, A.,Squires, I.J.,Owen, D.,Mott, H.R.
Calmodulin extracts the Ras family protein RalA from lipid bilayers by engagement with two membrane-targeting motifs.
Proc.Natl.Acad.Sci.USA, 118:-, 2021

PubMed Abstract: RalA is a small GTPase and a member of the Ras family. This molecular switch is activated downstream of Ras and is widely implicated in tumor formation and growth. Previous work has shown that the ubiquitous Ca-sensor calmodulin (CaM) binds to small GTPases such as RalA and K-Ras4B, but a lack of structural information has obscured the functional consequences of these interactions. Here, we have investigated the binding of CaM to RalA and found that CaM interacts exclusively with the C terminus of RalA, which is lipidated with a prenyl group in vivo to aid membrane attachment. Biophysical and structural analyses show that the two RalA membrane-targeting motifs (the prenyl anchor and the polybasic motif) are engaged by distinct lobes of CaM and that CaM binding leads to removal of RalA from its membrane environment. The structure of this complex, along with a biophysical investigation into membrane removal, provides a framework with which to understand how CaM regulates the function of RalA and sheds light on the interaction of CaM with other small GTPases, including K-Ras4B.

PubMed: 34480001
DOI: 10.1073/pnas.2104219118

Experimental method

SOLUTION NMR