The uptake of external proteases from the extracellular space occurs during signal transduction

Src-family kinases are not involved in signal transduction in B cells

Activates downstream signaling pathways, including the early phosphorylation of tyrosine residues on the ITAMs of Ig𝛼 and Ig𝛽 by Src 

Perforin is released during signal transduction

NF-κB is primarily responsible for phosphorylating the ITAMs