Enables actin filament binding activity. Involved in several processes, including actin filament organization; regulation of actin polymerization or depolymerization; and spicule insertion. Located in striated muscle thin filament. Expressed in several structures, including body wall musculature; germ line; intestine; non-striated muscle; and pharynx. Human ortholog(s) of this gene implicated in several diseases, including congenital myopathy (multiple); distal arthrogryposis type 1A; and intrinsic cardiomyopathy (multiple). Is an ortholog of several human genes including TPM1 (tropomyosin 1); TPM2 (tropomyosin 2); and TPM3 (tropomyosin 3).