Actin-binding protein involved in actin cytoskeleton regulation and dynamics. Increases the number and size of actin stress fibers and inhibits membrane ruffling. Inhibits actin filament depolymerization. Bundles actin filaments, delays filament nucleation and reduces formation of branched filaments (By similarity). Plays a role in cholesterol homeostasis. Influences plasma cholesterol levels through regulation of intestinal cholesterol absorption. May act as a scaffold protein by regulating NPC1L1 transportation, an essential protein for cholesterol absorption, to the plasma membrane by recruiting MYO5B to NPC1L1, and thus facilitates cholesterol uptake (PubMed:29880681). Interacts with NPC1L1; bridges NPC1L1 with MYO5B (PubMed:29880681). Interacts with MYO5B; bridges MYO5B with NPC1L1 (PubMed:29880681). Interacts with PXN; this complex stabilizes actin dynamics (By similarity). Binds to G-actin and F-actin (PubMed:17875928) (By similarity). Expressed mainly in the brush border membrane of the small intestine and colocalizes with NPC1L1 and MYO5B (PubMed:29880681). Colocalizes with PXN at focal adhesions in mesangial cells (By similarity). Colocalizes with actin stress fibers in quiescent cells. PDGF stimulation induced disassembly of stress fibers and formation of peripheral and dorsal ruffles, where LIMA1 is relocalized (PubMed:17875928). Highly expressed in the small intestine, including the duodenum, jejunum, and ileum. Low expression in the liver and very low expressed in the heart, spleen, lung, brain, and pancreas (PubMed:29880681). Isoform Alpha is highly expressed in embryos from day 7-11 and in adult spleen and lung. Isoform Beta expression is highest in adult kidney, testis, lung and liver, intermediate in heart, brain, spleen, skeletal muscle and low in embryos. Contains at least 2 actin-binding domains, one on each side of the LIM domain. Both domains bind actin monomers and filaments. The C-terminal domain binds filaments more efficiently than the N-terminus (By similarity). Phosphorylation of the C-terminal region by MAPK1/MAPK3 reduces its association with F-actin and contributes to actin filament reorganization and enhances cell motility. Deficient mice display reduced dietary cholesterol absorption.