P39-associated Cdk5 activity regulates dendritic morphogenesis

Li Ouyang,Ye Wang,Nancy Y Ip,Amy K Y Fu,Yu Chen,Wing-Yu Fu,Yuewen Chen

doi:10.1038/s41598-020-75264-6

Abstract

Dendrites, branched structures extending from neuronal cell soma, are specialized for processing information from other neurons. The morphogenesis of dendritic structures is spatiotemporally regulated by well-orchestrated signaling cascades. Dysregulation of these processes impacts the wiring of neuronal circuit and efficacy of neurotransmission, which contribute to the pathogeneses of neurological disorders. While Cdk5 (cyclin-dependent kinase 5) plays a critical role in neuronal dendritic development, its underlying molecular control is not fully understood. In this study, we show that p39, one of the two neuronal Cdk5 activators, is a key regulator of dendritic morphogenesis. Pyramidal neurons deficient in p39 exhibit aberrant dendritic morphology characterized by shorter length and reduced arborization, which is comparable to dendrites in Cdk5-deficient neurons. RNA sequencing analysis shows that the adaptor protein, WDFY1 (WD repeat and FYVE domain-containing 1), acts downstream of Cdk5/p39 to regulate dendritic morphogenesis. While WDFY1 is elevated in p39-deficient neurons, suppressing its expression rescues the impaired dendritic arborization. Further phosphoproteomic analysis suggests that Cdk5/p39 mediates dendritic morphogenesis by modulating various downstream signaling pathways, including PI3K/Akt-, cAMP-, or small GTPase-mediated signaling transduction pathways, thereby regulating cytoskeletal organization, protein synthesis, and protein trafficking.

Highlights

Dendrites, branched structures extending from neuronal cell soma, are specialized for processing information from other neurons
We determined whether p35- or p39-associated Cdk[5] activity regulates dendritic morphogenesis
P35-knockdown hippocampal neurons exhibited slightly enhanced dendritic complexity (Fig. 1e–h) compared to control neurons, suggesting that either p35 is dispensable for dendritic development or that p39 alone can sufficiently compensate for the loss of p35

Summary

Introduction

Dendrites, branched structures extending from neuronal cell soma, are specialized for processing information from other neurons. The expression of p35 protein is high throughout the embryonic stage, whereas that of p39 increases during postnatal d ifferentiation[4] Mice lacking both p35 and p39 exhibit inverted cortical lamination, aberrant neuronal morphology, and defective synaptic functions, which are observed in Cdk5-knockout m ice[18,19]. These observations suggest that the activity of Cdk[5] is attributable to its association with these two activators, which might have overlapping functions. RNA sequencing and mass spectrometry analyses of phosphoproteins suggest that p39 regulates dendritic complexity by modulating the expression of a signaling adaptor protein, WDFY1 (WD repeat and FYVE domain-containing protein 1). We identify multiple phosphorylationdependent signaling pathways that regulate cytoskeletal dynamics as well as protein synthesis and trafficking in p39-dependent dendritic morphogenesis

Methods

Results

Discussion

Conclusion