A single-chain chimeric polypeptide, wherein the single-chain chimeric polypeptide comprises: an extracellular antigen-binding domain; a transmembrane domain; an intracellular signaling domain; and a hormone receptor ligand binding domain, wherein: the transmembrane domain and the hormone receptor ligand binding domain directly abut each other or are separated by 1 to 700 amino acids; and the transmembrane domain and the hormone receptor ligand binding domain are not both present in the same endogenous single-chain polypeptide in a mammal; wherein the transmembrane domain comprises at least one contiguous amino acid sequence that traverses a lipid bilayer and has α-helical secondary structure in the lipid bilayer when present in a corresponding endogenous polypeptide when expressed in a mammalian cell; and wherein the hormone receptor ligand binding domain is a ligand binding domain from an estrogen receptor, a progesterone receptor, or an androgen receptor, wherein when the single-chain chimeric polypeptide is expressed in a cell, the hormone receptor ligand binding domain is extracellular and wherein: (i) when going in the N-terminal to C-terminal direction, the single-chain chimeric polypeptide comprises the extracellular antigen-binding domain, the extracellular hormone receptor ligand binding domain, the transmembrane domain, and the intracellular signaling domain; or (ii) when going in the C-terminal to N-terminal direction, the single-chain chimeric polypeptide comprises the extracellular antigen-binding domain, the extracellular hormone receptor ligand binding domain, the transmembrane domain, and the intracellular signaling domain. an extracellular antigen-binding domain; a transmembrane domain; an intracellular signaling domain; and a hormone receptor ligand binding domain, wherein: the transmembrane domain and the hormone receptor ligand binding domain directly abut each other or are separated by 1 to 700 amino acids; and the transmembrane domain and the hormone receptor ligand binding domain are not both present in the same endogenous single-chain polypeptide in a mammal; wherein the transmembrane domain comprises at least one contiguous amino acid sequence that traverses a lipid bilayer and has α-helical secondary structure in the lipid bilayer when present in a corresponding endogenous polypeptide when expressed in a mammalian cell; and wherein the hormone receptor ligand binding domain is a ligand binding domain from an estrogen receptor, a progesterone receptor, or an androgen receptor, wherein when the single-chain chimeric polypeptide is expressed in a cell, the hormone receptor ligand binding domain is extracellular and wherein: (i) when going in the N-terminal to C-terminal direction, the single-chain chimeric polypeptide comprises the extracellular antigen-binding domain, the extracellular hormone receptor ligand binding domain, the transmembrane domain, and the intracellular signaling domain; or (ii) when going in the C-terminal to N-terminal direction, the single-chain chimeric polypeptide comprises the extracellular antigen-binding domain, the extracellular hormone receptor ligand binding domain, the transmembrane domain, and the intracellular signaling domain. the transmembrane domain and the hormone receptor ligand binding domain directly abut each other or are separated by 1 to 700 amino acids; and the transmembrane domain and the hormone receptor ligand binding domain are not both present in the same endogenous single-chain polypeptide in a mammal; wherein the transmembrane domain comprises at least one contiguous amino acid sequence that traverses a lipid bilayer and has α-helical secondary structure in the lipid bilayer when present in a corresponding endogenous polypeptide when expressed in a mammalian cell; and wherein the hormone receptor ligand binding domain is a ligand binding domain from an estrogen receptor, a progesterone receptor, or an androgen receptor, wherein when the single-chain chimeric polypeptide is expressed in a cell, the hormone receptor ligand binding domain is extracellular and wherein: (i) when going in the N-terminal to C-terminal direction, the single-chain chimeric polypeptide comprises the extracellular antigen-binding domain, the extracellular hormone receptor ligand binding domain, the transmembrane domain, and the intracellular signaling domain; or (ii) when going in the C-terminal to N-terminal direction, the single-chain chimeric polypeptide comprises the extracellular antigen-binding domain, the extracellular hormone receptor ligand binding domain, the transmembrane domain, and the intracellular signaling domain. (i) when going in the N-terminal to C-terminal direction, the single-chain chimeric polypeptide comprises the extracellular antigen-binding domain, the extracellular hormone receptor ligand binding domain, the transmembrane domain, and the intracellular signaling domain; or (ii) when going in the C-terminal to N-terminal direction, the single-chain chimeric polypeptide comprises the extracellular antigen-binding domain, the extracellular hormone receptor ligand binding domain, the transmembrane domain, and the intracellular signaling domain.