The SH3 domain-binding PxxPxR motif (750-755) in mouse Focal adhesion kinase 1 that binds the SH3 domain of a v-Crk-associated tyrosine kinase substrate, p130Cas (Breast cancer anti-estrogen resistance protein 1 or Bcar1). This motif, and its interaction it mediates, may be important in the invasion of host cells by Salmonella typhimurium