May play an important role in the heart development by scaffolding PKC to the Z-disk region. May play a role in the regulation of cardiomyocyte expansion. Isoforms lacking the LIM domains may negatively modulate the scaffolding activity of isoform 1. Overexpression promotes the development of heart hypertrophy. Contributes to the regulation of dendritic spine morphogenesis in neurons. May be required to restrain postsynaptic growth of excitatory synapses. Isoform 1, but not isoform 2, expression favors spine thinning and elongation. Interacts with various PKC isoforms through the LIM domains. Interacts with actin and alpha-actinin through the PDZ domain. Interacts (via LIM domains) with SIPA1L1/SPAR; this interaction may occur preferentially with isoform 1. Detected both at presynaptic and postsynaptic sites, exclusively at excitatory synapses, but not inhibitory synapses, in hippocampal neurons.