Amots are adaptor proteins which coordinate signaling for cellular differentiation and proliferation. Their ACCH domain binds lipids with specificity leading to membrane deformation. A critical feature of Amot proteins is a novel lipid-binding domain, the Amot coiled-coil homology (ACCH) domain, which has the ability to selectively bind monophosphorylated phosphatidylinositols (PI) as well as target transcription factors to the nucleus. Understanding the biophysical mechanisms involved in lipid binding may provide pathways to modulate protein sorting and downstream signaling events inducing cellular differentiation, cancer cell proliferation, and migration. The central hypothesis is that characterizing Amot lipid-binding events will enable specific modulation of Amot isozyme for the prevention of ductal cell hyperplasia progression into breast cancer tumors. Synthetic membranes are used to demonstrate the role of dimerization in the ability to maintain ACCH-lipid binding activity. The specific aims of this work are: 1) Delineate the properties of the ACCH domain that provide for a dimer switch; and 2). Define the lipid-interaction properties of the ACCH domain homo- and hetero-dimer.Site-directed mutagenesis was employed to probe the specific contributions of 37 selected lysines and arginines. We first measured the mutation stability through DSF, and then for their ability to dimerize using DLS. We then compare that information with that garnered from intrinsic tyrosine absorbance to understand the changes in structural conformations as a function of the mutation and lipid binding. As a result, we look to provide further information about which conserved residues participate in dimerization as a mechanism to control hetero- and homo-dimer formation.This work was supported by the IUSM LHSI Program and NIH K01CA169078-01.