Protein kinase C-δ and -β coordinate flow-induced directionality and deformation of migratory human blood T-lymphocytes

Abstract

T-lymphocyte migration under flow is critical for immune responses, but the mechanisms by which flow modulates the migratory behaviors of T-lymphocytes remain unclear. Human peripheral blood T-lymphocytes (PBTLs), when stimulated with phorbol 12-myristate 13-acetate (PMA), stretched their cell bodies dramatically and moved along the flow direction. In contrast, stromal cell-derived factor-1α-stimulated PBTLs deformed and migrated in a random manner. Here we elucidated the molecular mechanisms underlying flow-induced directionality and deformation of PMA-stimulated PBTLs. PMA primed PBTLs for polarization under flow, with protein kinase C (PKC)-δ enriched in the leading edge, PKC-βI in the microtubule organizing center, and PKC-βII in the uropod and peripheral region. PKC-δ regulated cell protrusions in the leading edge through Tiam1/Rac1/calmodulin, whereas PKC-β regulated RhoA/Rho-associated kinase activity and microtubule stability to modulate uropod contractility and detachment. Our findings indicate that PKC-δ and -β coordinate in the cell leading edge and uropod, respectively, to modulate the directionality and deformability of migratory T-lymphocytes under flow.

Identification of miR-34a-target interactions by a combined network based and experimental approach

“…Additionally a study of Grybko et al showed that PRKCA translocates in synergy with PRKCQ to the IS of cytotoxic T-cells to mediate lytic granule exocytosis [63]. PRKCB coordinates together with PRKCD the responsiveness of migratory human blood T-lymphocytes [64]. Various PKC knockout studies analyzing PRKCA -, PRKCB -, PRKCE -, PRKCH - or PRKCQ -deficient mice observed defects in immune cell activation and function [65–69].…”

Origins of the cytolytic synapse

“…These initial contacts occur via actin-rich protrusions at the leading edge of migrating T cells, which are regulated by protein kinase Cδ (PKCδ), RAC1 and downstream effectors of actin polymerization including Wiskott Aldrich syndrome protein (WASP) 28 . These protrusions form the first point of contact between cells as synapses form, and they may correspond to the actin foci that have been reported to be required for the activation of PLCγ1, via WASP 29 .…”

The deterministic role of 5-mers in microRNA-gene targeting

“…Illustration on the underlying algorithm to detect miRNA k-mer enrichments in possible target sequences. Human mature miRNA 5p/3p sequences were collected from miRBase v21, while 3 0 UTRs for human were acquired from Ensembl Release 91 [51]. After extracting and mapping the k-mers with up to 2 mismatches for each possible binding site, the best k-mer was selected.…”

“…Recently, we identified miR-34a as most up-regulated miRNA in CD3+ T cells of lung cancer patients targeting five protein kinase C family members including PRKCA, PRKCB, PRKCE, PRKCH and PRKCQ [31]. Besides the central role of these PKC isozymes in carcinogenesis, these miR-34a target genes are involved in cell signaling through the immunological synapse (IS) of T cells downstream of the T cell receptor (TCR) [47][48][49][50][51].…”