Interaction of N-WASP with hnRNPK and its role in filopodia formation and cell spreading.
N-WASP is a member of the WASP family of proteins, which play essential roles in actin dynamics during cell adhesion and migration. hnRNPK is a member of the heterogeneous nuclear ribonucleoprotein complex, which has also been implicated in the regulation of cell spreading. Here, we identify a direct interaction between N-WASP and hnRNPK. We show that this interaction is mediated by the N-terminal WH1 domain of N-WASP and the segment of hnRNPK containing its K interaction (KI) domain. Furthermore, these two proteins are co-localized at the cell periphery in the spreading initiation center during the early stage of cell spreading. We found that co-expression of hnRNPK with N-WASP reverses the stimulation of cell spreading by N-WASP, and this effect is correlated with hnRNPK binding to N-WASP. Expression of hnRNPK does not affect subcellular localization of N-WASP protein. However, co-expression of hnRNPK with N-WASP reduced filopodia formation stimulated by N-WASP in spreading cells. Together, these results identify hnRNPK as a new negative regulator of N-WASP and suggest that hnRNPK may regulate the initial stage of cell spreading by direct association with N-WASP in the spreading initiation center.
Department of Molecular Medicine, Cornell University, Ithaca, New York 14853, USA.
Youngdong
Y
Yoo
Xiaoyang
X
Wu
Coumaran
C
Egile
Rong
R
Li
Jun-Lin
JL
Guan
D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D006224:Cricetinae; D034641:Heterogeneous-Nuclear Ribonucleoprotein K / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D051379:Mice; D017434:Protein Structure, Tertiary; D011554:Pseudopodia / Q000502:physiology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal / Q000737:chemistry / Q000235:genetics / Q000502:physiology*
D034641:Heterogeneous-Nuclear Ribonucleoprotein K; D011994:Recombinant Proteins; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal