Attaches the virus to cell receptors and thereby initiating infection. Binding of H protein to the receptor induces a conformational change that allows the F protein to trigger virion/cell membranes fusion. May use human CD46 and/or SLAMF1 as receptors for viral entry into the cell. The high degree of interaction between H and MCP/CD46 results in down-regulation of the latter from the surface of infected cells, rendering them more sensitive to c3b-mediated complement lysis. Interacts with human NECTIN4; this interaction allows virus infection of the respiratory epithelium (By similarity). Interacts with human MCP/CD46 antigen and SLAMF1. Belongs to the paramyxoviruses hemagglutinin-neuraminidase family. Non-sialidase subfamily. Morbiliviruses hemagglutinins have no neuraminidase activity.