Unconventional myosin required during immune response for detection of rare antigen-presenting cells by regulating T-cell migration. Unconventional myosins are actin-based motor molecules with ATPase activity and serve in intracellular movements. Acts as a regulator of T-cell migration by generating membrane tension, enforcing cell-intrinsic meandering search, thereby enhancing detection of rare antigens during lymph-node surveillance, enabling pathogen eradication. Also required in B-cells, where it regulates different membrane/cytoskeleton-dependent processes. Involved in Fc-gamma receptor (Fc-gamma-R) phagocytosis. Constitutes the minor histocompatibility antigen HA-2. More generally, minor histocompatibility antigens (mHags) refer to immunogenic peptide which, when complexed with MHC, can generate an immune response after recognition by specific T-cells. The peptides are derived from polymorphic intracellular proteins, which are cleaved by normal pathways of antigen processing. The binding of these peptides to MHC class I or class II molecules and their expression on the cell surface can stimulate T-cell responses and thereby trigger graft rejection or graft-versus-host disease (GVHD) after hematopoietic stem cell transplantation from HLA-identical sibling donor. GVHD is a frequent complication after bone marrow transplantation (BMT), due to mismatch of minor histocompatibility antigen in HLA-matched sibling marrow transplants. HA-2 is restricted to MHC class I HLA-A*0201. Interacts with calmodulin; via its IQ motifs. Recruited to Fc-gamma receptor (Fc-gamma-R) phagocytic cup. In T-cells, transiently accumulates in discrete areas at the plasma membrane of migrating cells or when membranes are deformed (By similarity). Localization at the membrane is not highly dependent on phosphatidylinositol 4,5-bisphosphate levels. Released from the membrane in the presence of ATP. May be enriched in peripheral processes, such as microvilli or ruffles. Specifically expressed in hematopoietic cells. The myosin tail domain mediates binding to phosphatidylinositol-3,4-bisphosphate (PtdIns(3,4)P2), phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2) and phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P3) and binds to membranous compartments. It is required for recruitment to Fc-gamma receptor (Fc-gamma-R) phagocytic cups. Belongs to the TRAFAC class myosin-kinesin ATPase superfamily. Myosin family. Represents an unconventional myosin. This protein should not be confused with the conventional myosin-1 (MYH1). Wrong choice of CDS.