Subcellular localization and differentiation-induced redistribution of the protein tyrosine phosphatase PTP-BL in Neuroblastoma cells.
1. In cells of epithelial origin the protein tyrosine phosphatase PTP-BL is predominantly localized at the apical membrane of polarized cells. This large submembranous multidomain PTP is also expressed in cells of neuronal origin. We studied the localization of PTP-BL in mouse neuroblastoma cells utilizing EGFP-tagged versions of the protein. 2. In proliferating Neuro-2a cells, immunofluorescence and immuno-electron microscopy revealed a submembranous FERM domain-dependent localization at cell-cell boundaries for EGFP-PTP-BL. Additionally, significant amounts of EGFP-PTP-BL are located in the cytoplasm as well as in nuclei. Upon serum depletion-induced differentiation of Neuro-2a cells, a partial shift of EGFP-PTP-BL from a cortical localization to cytoskeleton-like F-actin-positive structures is observed. Parallel biochemical studies corroborate this finding and reveal a serum depletion-induced shift of EFGP-PTP-BL from a membrane(-associated) fraction to an NP40-soluble cytoskeletal fraction. 3. Different pools of PTP-BL-containing protein complexes can be discerned in neuronal cells, reflecting distinct molecular microenvironments in which PTP-BL may exert its function.
van Ham
Marco
M
Department of Cell Biology, Institute of Cellular Signalling, Nijmegen Centre for Molecular Life Sciences, Radbound University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Kemperman
Lottie
L
Wijers
Mietske
M
Fransen
Jack
J
Hendriks
Wiljan
W
D008841:Actin Cytoskeleton / Q000201:enzymology / Q000648:ultrastructure; D000199:Actins / Q000378:metabolism; D000818:Animals; D002451:Cell Compartmentation / Q000187:drug effects / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000201:enzymology* / Q000648:ultrastructure; D002467:Cell Nucleus / Q000201:enzymology / Q000648:ultrastructure; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D003593:Cytoplasm / Q000201:enzymology / Q000648:ultrastructure; D003599:Cytoskeleton / Q000201:enzymology* / Q000648:ultrastructure; D049452:Green Fluorescent Proteins; D046911:Macromolecular Substances / Q000378:metabolism; D051379:Mice; D009447:Neuroblastoma; D009474:Neurons / Q000201:enzymology* / Q000648:ultrastructure; D017434:Protein Structure, Tertiary / Q000502:physiology; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D054595:Protein Tyrosine Phosphatase, Non-Receptor Type 13; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000378:metabolism*
D000199:Actins; D016895:Culture Media, Serum-Free; D046911:Macromolecular Substances; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D054595:Protein Tyrosine Phosphatase, Non-Receptor Type 13; D017027:Protein Tyrosine Phosphatases; C516743:Ptpn13 protein, mouse