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 (By similarity). Interacts with NPC1L1; bridges NPC1L1 with MYO5B. Interacts with MYO5B; bridges MYO5B with NPC1L1 (By similarity). Interacts with PXN; this complex stabilizes actin dynamics. Interacts with F-actin and G-actin (By similarity). This cytoskeletal protein colocalizes with actin stress fibers and focal adhesion plaques. Expressed mainly in the brush border membrane of the small intestine and colocalizes with NPC1L1 and MYO5B (By similarity). 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 (By similarity). Widely expressed. Highest levels of isoform 2 are expressed in lung, spleen and small intestine. Isoform 2 is expressed at higher levels than isoform 1 in most tissues except liver, fat and kidney. Isoform 1 and isoform 2 are expressed at low levels in skeletal muscle, heart, stomach and lymph. Isoform 1 is expressed at low levels at embryonic day 33 (E33) and in the adult. Isoform 2 is expressed abundantly throughout embryonic development with a peak at E65 and is expressed at lower levels in the neonate and adult. Isoform 1 and isoform 2 are expressed at similar levels in the adult. 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.