TY - JOUR
T1 - Identification and characterization of homologues of vertebrate β-thymosin in the marine mollusk Aplysia californica
AU - Romanova, Elena Vikentievna
AU - Roth, Michael J.
AU - Rubakhin, Stanislav
AU - Jakubowski, Jennifer A.
AU - Kelley, Wayne P.
AU - Kirk, Mark D.
AU - Kelleher, Neil L.
AU - Sweedler, Jonathan V
PY - 2006/8
Y1 - 2006/8
N2 - The β-thymosins have been known as actin-sequestering proteins, but now are recognized as molecules with multiple and diverse intracellular and extracellular functions. Two closely related proteins, β-thymosin His and β-thymosinGln, have been de novo sequenced by top-down mass spectrometry in the common neurobiology model, Aplysia californica. As determined by nanoelectrospray quadrupole-enhanced Fourier-Transform mass spectrometry with collisionally activated and electron-capture dissociations, both of these Aplysia β-thymosins are acetylated and differ by a single residue in the central actin-binding domain. Profiling of individual cells and tissue by matrix-assisted laser desorption/ionization mass spectrometry reveals that these proteins are widely expressed in the Aplysia central nervous system, including in individual identified neurons, neuronal clusters, nerves and connective tissues. Newly identified β-thymosinHis and β-thymosinGln are also detected by mass spectrometry in hemolymph, and in releasates collected from whole ganglia. When applied exogenously, β-thymosin proteins, purified from nerve cell extract, support the anchoring of neurons, and increase neurite sprouting and total neurite outgrowth in culture. These positive effects on neurite regeneration in cell culture suggest that the β-thymosin proteins have an extracellular function in the central nervous system of Aplysia californica.
AB - The β-thymosins have been known as actin-sequestering proteins, but now are recognized as molecules with multiple and diverse intracellular and extracellular functions. Two closely related proteins, β-thymosin His and β-thymosinGln, have been de novo sequenced by top-down mass spectrometry in the common neurobiology model, Aplysia californica. As determined by nanoelectrospray quadrupole-enhanced Fourier-Transform mass spectrometry with collisionally activated and electron-capture dissociations, both of these Aplysia β-thymosins are acetylated and differ by a single residue in the central actin-binding domain. Profiling of individual cells and tissue by matrix-assisted laser desorption/ionization mass spectrometry reveals that these proteins are widely expressed in the Aplysia central nervous system, including in individual identified neurons, neuronal clusters, nerves and connective tissues. Newly identified β-thymosinHis and β-thymosinGln are also detected by mass spectrometry in hemolymph, and in releasates collected from whole ganglia. When applied exogenously, β-thymosin proteins, purified from nerve cell extract, support the anchoring of neurons, and increase neurite sprouting and total neurite outgrowth in culture. These positive effects on neurite regeneration in cell culture suggest that the β-thymosin proteins have an extracellular function in the central nervous system of Aplysia californica.
KW - Acetylation
KW - Nanoelectrospray quadrupole-enhanced Fourier-Transform mass spectrometry
KW - Neurons
KW - Single-cell matrix-assisted laser desorption/ionization mass spectrometry
KW - Top-down approach
UR - http://www.scopus.com/inward/record.url?scp=33748355839&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33748355839&partnerID=8YFLogxK
U2 - 10.1002/jms.1060
DO - 10.1002/jms.1060
M3 - Article
C2 - 16924592
AN - SCOPUS:33748355839
SN - 1076-5174
VL - 41
SP - 1030
EP - 1040
JO - Journal of Mass Spectrometry
JF - Journal of Mass Spectrometry
IS - 8
ER -