LIMA1
Domain
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.
Function
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 (PubMed:12566430). 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).
Post-translational modifications
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.
Tissue Specificity
Highly expressed in placenta, kidney, pancreas, prostate, ovary, spleen and heart. Also detected in lung, liver, brain, skeletal muscle, thymus, testis and intestine. Not detected in leukocytes. Isoform Beta expressed generally at very low levels. Isoform Alpha abundant in epithelial cells from mammary gland, prostate and in normal oral keratinocytes. Low levels in aortic endothelial cells and dermal fibroblasts. Not detectable in myocardium.
Cellular localization
- Cytoplasm
- Cell junction
- Focal adhesion
- Cytoplasm
- Cytoskeleton
- Cytoplasm
- Cytoskeleton
- Stress fiber
- Cell membrane
- Expressed 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 (PubMed:24694988). 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).
Alternative names
EPLIN, SREBP3, PP624, LIMA1, LIM domain and actin-binding protein 1, Epithelial protein lost in neoplasm