Forms membrane-associated dynamic filaments that are essential for cell shape determination (PubMed:14982627, PubMed:17880425, PubMed:24843005). Acts by regulating cell wall synthesis and cell elongation, and thus cell shape (PubMed:14982627, PubMed:17880425). A feedback loop between cell geometry and MreB localization may maintain elongated cell shape by targeting cell wall growth to regions of negative cell wall curvature (By similarity). Required for mid-cell peptidoglycan synthesis and cell division. Directs the localization of the cytosolic peptidoglycan precursor-synthesizing enzyme MurG (PubMed:17880425). Also required for proper chromosome segregation (PubMed:15707892). Directs the segregation of origin-proximal but not origin-distal loci (PubMed:15707892). Forms polymers in the presence of ATP. Forms pairs of protofilaments that adopt an antiparallel arrangement and bind to lipids. Membrane-associated (PubMed:14982627). Localizes as bands or spirals that encircled the cell along its entire length and switches to a mid-cell location at a time that coincided with the initiation of cell division. Localization at mid-cell depends on FtsZ (PubMed:14982627). Depletion results in lemon-shaped cells that possess defects in the integrity of the cell wall. Belongs to the FtsA/MreB family.