Figure 6.

Cas is a substrate of Src family tyrosine kinases in the developing mouse cerebella. (A) Coimmunoprecipitation of Cas with the Src family PTKs in the mouse cerebella. An equal quantity of protein lysates from P7 cerebella was first immunoprecipitated by Src, Fyn, Yes, Lyn, Hck, Lck, Zap70, Fak, or Pyk2 antibodies and then immunoblotted by the Cas antibody. (B) Src family PTK inhibitor PP2 inhibited tyrosine phosphorylation of Cas in cerebellar neurons. Primary cultured cerebellar neurons were treated with dimethyl sulfoxide, PP2, or a noninhibitory analog, PP3, at the indicated concentrations for 20 min, and the cell lysates were immunoblotted for YP-Cas. The same membrane was reblotted to indicate the quantity of Cas in each lane. (C) Cas (red) colocalizes with Src or Fyn (green) in the growth cones of cultured cerebellar granule cells. Cerebellar granule cells were fixed at DIV1, stained, and imaged using confocal microscopy.