F-actin cross-linking protein which is thought to anchor actin to a variety of intracellular structures. This is a bundling protein. Probably involved in vesicular trafficking via its association with the CART complex. The CART complex is necessary for efficient transferrin receptor recycling but not for EGFR degradation. Involved in tight junction assembly in epithelial cells probably through interaction with MICALL2. Links MICALL2 to the actin cytoskeleton and recruits it to the tight junctions. May also function as a transcriptional coactivator, stimulating transcription mediated by the nuclear hormone receptors PPARG and RARA. Homodimer; antiparallel. Interacts with MAGI1 (By similarity). Interacts with MICALL2 (preferentially in opened conformation); stimulated by RAB13 activation (By similarity). Identified in a IGF2BP1-dependent mRNP granule complex containing untranslated mRNAs (By similarity). Component of the CART complex, at least composed of ACTN4, HGS/HRS, MYO5B and TRIM3 (By similarity). Binds TRIM3 at the N-terminus (By similarity). Interacts with PDLIM2 (PubMed:15505042). Identified in a complex with CASK, IQGAP1, MAGI2, NPHS1, SPTAN1 and SPTBN1 (PubMed:15994232). Interacts with PPARG and RARA (By similarity). Binds to VCL; this interaction triggers VCL conformational changes (By similarity). Interacts with SEPTIN14 (By similarity). Localized in cytoplasmic mRNP granules containing untranslated mRNAs. Expressed in the perinuclear rim and manchette structure in early elongating spermatids during spermiogenesis (By similarity). Expressed in the foot process layer of podocytes in the kidney glomerulus but not in tubules (at protein level). Contains one Leu-Xaa-Xaa-Leu-Leu (LXXLL) motif that mediates interaction with nuclear receptors. Belongs to the alpha-actinin family.