Calcium-independent; phospholipid- and diacylglycerol (DAG)-dependent serine/threonine-protein kinase that mediates non- redundant functions in T-cell receptor (TCR) signaling; including T-cells activation; proliferation; differentiation and survival; by mediating activation of multiple transcription factors such as NF-kappa-B; JUN; NFATC1 and NFATC2. In TCR-CD3/CD28-co-stimulated T-cells; is required for the activation of NF-kappa-B and JUN; which in turn are essential for IL2 production; and participates to the calcium-dependent NFATC1 and NFATC2 transactivation. Mediates the activation of the canonical NF-kappa-B pathway (NFKB1) by direct phosphorylation of CARD11 on several serine residues; inducing CARD11 association with lipid rafts and recruitment of the BCL10-MALT1 complex; which then activates IKK complex; resulting in nuclear translocation and activation of NFKB1. May also play an indirect role in activation of the non- canonical NF-kappa-B (NFKB2) pathway. In the signaling pathway leading to JUN activation; acts by phosphorylating the mediator STK39/SPAK and may not act through MAP kinases signaling. Plays a critical role in TCR/CD28-induced NFATC1 and NFATC2 transactivation by participating in the regulation of reduced inositol 1;4;5-trisphosphate generation and intracellular calcium mobilization. After costimulation of T-cells through CD28 can phosphorylate CBLB and is required for the ubiquitination and subsequent degradation of CBLB; which is a prerequisite for the activation of TCR. During T-cells differentiation; plays an important role in the development of T-helper 2 (Th2) cells following immune and inflammatory responses; and; in the development of inflammatory autoimmune diseases; is necessary for the activation of IL17-producing Th17 cells. May play a minor role in Th1 response. Upon TCR stimulation; mediates T-cell protective survival signal by phosphorylating BAD; thus protecting T-cells from BAD-induced apoptosis; and by up-regulating BCL-X(L)/BCL2L1 levels through NF-kappa-B and JUN pathways. In platelets; regulates signal transduction downstream of the ITGA2B; CD36/GP4; F2R/PAR1 and F2RL3/PAR4 receptors; playing a positive role in 'outside-in' signaling and granule secretion signal transduction. May relay signals from the activated ITGA2B receptor by regulating the uncoupling of WASP and WIPF1; thereby permitting the regulation of actin filament nucleation and branching activity of the Arp2/3 complex. May mediate inhibitory effects of free fatty acids on insulin signaling by phosphorylating IRS1; which in turn blocks IRS1 tyrosine phosphorylation and downstream activation of the PI3K/AKT pathway. Phosphorylates MSN (moesin) in the presence of phosphatidylglycerol or phosphatidylinositol. Phosphorylates PDPK1 at 'Ser-504' and 'Ser-532' and negatively regulates its ability to phosphorylate PKB/AKT1. {ECO:0000269|PubMed:10746729; ECO:0000269|PubMed:12782715; ECO:0000269|PubMed:1508194; ECO:0000269|PubMed:15263025; ECO:0000269|PubMed:16493044; ECO:0000269|PubMed:19047061}.