  The spatio-temporal organization of proteins and the associated morphological
changes in membranes are of importance in cell signaling. Several mechanisms
that promote the aggregation of proteins at low cell surface concentrations
have been investigated in the past. We show, using Monte Carlo simulations,
that the affinity of proteins for specific lipids can hasten its aggregation
kinetics. The lipid membrane is modeled as a dynamically triangulated surface
with the proteins defined as in-plane fields at the vertices. We show that,
even at low protein concentrations, strong lipid-protein interactions can
result in large protein clusters indicating a route to lipid mediated signal
amplification. At high protein concentrations the domains form buds similar to
that seen in lipid-lipid interaction induced phase separation. Protein
interaction induced domain budding is suppressed when proteins act as
anisotropic inclusions and exhibit nematic orientational order. The kinetics of
protein clustering and resulting conformational changes are shown to be
significantly different for the isotropic and anisotropic curvature inducing
proteins.
