Table 1.

Summary of all proteins, chimeras, and point and deletion mutants used in this study.

Protein/chimera/mutantNomenclatureLocalizationFilopodia numberTubule number% Neurons in stage 1
CIP4SCCSCCCP<1<190
CIP4S SH3 swapCCSCCFP<11–290
CIP4S + FBP17 L1S swapCFSCCCP<1<1ND
FBP17 + CIP4 L1S/HR1/L2 swapFCSCCFP<1<185
FBP17 C-terminal swapFCSCCCP1–21–260
CIP4S ΔL2+SH3CCSC- -P1–21–255a
CIP4S ΔSH3CCSCC-P0–11–255a
FBP17S + CIP4 HR1 swapFFSCFFP1–21–2ND
CIP4L PxxP region mutantCIP4L-AxxAP1–22–4ND
FBP17S ΔL2+SH3FFSC- -PNDNDND
FBP17 L1 swapFCSFFFP1–2<165
CIP4S HR1 swapCCSFCCP/C2–4<165
GFP- - - - -C2–4<160
FBP17SFFSFFFC1–2<1ND
CIP4S PBR mutantCIP4S-7QC1–2<1ND
CIP4L PBR mutantCIP4L-7QC1–2<1ND
CIP4 ΔL1C-CCCC1–2<1ND
CIP4 F-BAR/EFC (1–300)C- - - -C1–2<1ND
CIP4 F-BAR/EFC + L1S(7Q)CCS- - -7QCNDNDND
CIP4 F-BAR/EFC + L1L (7Q)CCL- - -7QCNDNDND
FBP17 ΔL1F-FFFC1–2<1ND
FBP17 F-BAR/EFC (1–300)F- - - -C1–3<1ND
FBP17L PxxP region mutantFBP17L-AxxAV/T1–21–3ND
FBP17 F-BAR/EFC + L1SFFS- - -TNDNDND
CIP4 F-BAR/EFC + L1SCCS- - -T2–33–6ND
CIP4LCCLCCCT1–24–8ND
CIP4 F-BAR/EFC + L1LCCL- - -TNDNDND
FBP17 F-BAR/EFC + L1LFFL- - -T2–34–8ND
CIP4 C-terminal swapCFLFFFT2–44–850
CIP4 L1 swapCFLCCCT2–46–1245
CIP4 + FBP17 L1L/HR1/L2 swapCFLFFCT1–36–1240
FBP17L SH3 swapFFLFFCT2–43–640
FBP17L HR1 swapFFLCFFT2–44–845
FBP17LFFLFFFT2–46–1235
  • C, cytosol; ND, not determined; P, periphery; T, tubule; V, vesicle. Shading depicts the most CIP4S (orange) to the most FBP17L (blue) phenotype.

  • Staging determined at 12 h in vitro, Filopodia number is expressed per 10 µm of cell perimeter, and Tubule number is expressed per cell.

  • a In this set of experiments, only 75% of CIP4S neurons were in stage 1.