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Fig. 4. pFAK staining is influenced by factors that reduce LLT frequency. (A) Growth cones of cells grown in 0 mM Ca2+ are more densely stained than those of cells
grown in 2 mM Ca2+ (Fig. 3A). (B, C) Light staining in the presence of osmotically balanced 30 mM extracellular Ca2+ is converted to dense staining by exposure to
100 nM BAPTA-AM. (D) The mean pFAK staining intensity is decreased significantly when cells are grown in the presence of extracellular Ca2+; this effect is blocked
by addition of BAPTA to suppress elevation of intracellular Ca2+ (Gu and Spitzer, 1995). n > 20 growth cones for each condition. Asterisk denotes statistically
different from 0 mMCa2+ and 30 mM Ca2+ plus BAPTA (p < 0.05). (E) pFAK staining is more intense in cells grown in 2 mMCa2+ on tenascin where LLTs are absent
than on tissue culture plastic where LLTs are present; arrows identify two growth cones on these different substrates in the same culture, �200 Am apart. |
