text: A protein in the HSP70 family that is localized to the ER is named for "binding" to these molecules.
full_question: A protein in the HSP70 family that is localized to the ER is named for "binding" to these molecules. The kinetoplast of Crithidia luciliae is used to detect examples of these entities that bind to dsDNA. The binding of these proteins to their substrates can produce C3 convertase and trigger the classical complement pathway. These proteins are used to visualize indirect fluorescence, in which (*) secondary types of these proteins bind primary ones in a technique commonly used with Western blots. One of these proteins, rheumatoid factor, binds to the Fc region of another of these proteins. These proteins, made of two heavy chains and two light chains, are secreted by B cells. For 10 points, name these Y-shaped proteins which bind to antigens.
first_sentence: A protein in the HSP70 family that is localized to the ER is named for "binding" to these molecules.